Electron beam resist composition

ABSTRACT

The present invention relates to an electron beam (eBeam) resist composition, particularly an (eBeam) resist composition for use in the fabrication of integrated circuits. Such resist compositions include an anti-scattering compound which minimises scattering and secondary electron generation, thus affording extremely high resolution lithography. Such high resolution lithography may be used directly upon silicon-based substrates to produce integrated circuits, or may alternatively be used to produce a lithographic mask (e.g. photomask) to facilitate high-resolution lithography.

INTRODUCTION

The present invention relates to an electron beam (eBeam) resistcomposition, particularly an (eBeam) resist composition for use in thefabrication of integrated circuits. The present invention also relatesto an eBeam resist-coated material/substrate and method for itspreparation, a patterned substrate and method for its preparation, amethod of imaging, a method of performing electron-beam lithography andan imaged substrate formed from said method, a method of selectivelymodifying a surface of a substrate, a lithographic mask and method forits preparation, a method of performing lithography with saidlithographic mask and an imaged substrate formed from said method, amulti-layered substrate and a method for its preparation, an integratedcircuit die or an integrated circuit wafer comprising a plurality ofintegrated circuit dice and methods for their preparation, an integratedcircuit package and method for its preparation, a circuit board and itsmethod of preparation, an electronic device or system and its method ofpreparation, and a use of an eBeam resist composition to produce all theabove.

BACKGROUND

There is a continuous drive in the electronics industry to miniaturizeintegrated circuits, for a variety of reasons well known to thoseskilled in the art. Significant developments in the semiconductorindustry were made possible by advances in photolithography, from themicron scale to the nanometer scale, but the physical resolution limitsof optical lithography have now almost been reached, thus constrainingfurther advancement. However, continued growth of the semiconductorindustry depends on increasing the performance of integrated circuits ona silicon substrate.

Recent developments in extreme ultraviolet (EUV) lithography, at 13.5nm, has enabled some further scaling/miniaturization of integratedcircuits, but enormous challenges still obstruct the full implementationof this technique in the semiconductor industry.

Electron-beam lithography (e-beam, EBL) has been considered as apotential complement to optical lithography on account of its highresolution. However, even this high resolution is somewhat limited bythe nature of the eBeam resists currently available, which tend toscatter primary electrons, thus producing secondary electrons andproximity effects which compromise the resolution and clarity of theultimate printed pattern.

It is therefore an object of the present invention to solve at least oneof the problems of the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is providedan eBeam resist composition comprising an anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of preparing an eBeam resist-coated material/substrate, themethod comprising coating a substrate with an eBeam resist coating;wherein the eBeam resist coating comprises an optionally dried and/orcured eBeam resist composition; and wherein the eBeam resist compositioncomprises an anti-scattering compound.

According to a further aspect of the invention, there is provided aneBeam resist-coated material/substrate obtainable by, obtained by, ordirectly obtained by a method of preparing an eBeam resist-coatedmaterial/substrate as defined herein.

According to a further aspect of the invention, there is provided aneBeam resist-coated material/substrate comprising a substrate coatedwith an eBeam resist coating; wherein the eBeam resist coating comprisesan optionally dried and/or cured eBeam resist composition; wherein theeBeam resist composition comprises an anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of preparing a patterned substrate, the method comprising:

-   -   i) providing an eBeam resist-coated substrate as defined herein        or applying an eBeam resist coating to a substrate;    -   ii) exposing part(s) of the eBeam resist coating to electron        beam radiation to provide an exposed eBeam resist coating;    -   iii) developing the exposed eBeam resist coating to generate an        eBeam resist pattern layer, the eBeam resist pattern layer        comprising: developer-insoluble coating portions of the eBeam        resist coating (i.e. ridges); and an array of grooves extending        through the eBeam resist pattern layer;        wherein the eBeam resist coating comprises an optionally dried        and/or cured eBeam resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided apatterned substrate obtainable by, obtained by, or directly obtained bya method of preparing a patterned substrate as defined herein.

According to a further aspect of the invention, there is provided amethod of imaging, the method comprising:

-   -   i) providing an eBeam resist-coated substrate as defined herein        or applying an eBeam resist coating to a substrate;    -   ii) exposing part(s) of the eBeam resist coating to electron        beam radiation to provide an exposed eBeam resist coating;    -   iii) developing the exposed eBeam resist coating to generate an        eBeam resist pattern layer, the eBeam resist pattern layer        comprising: developer-insoluble coating portions of the eBeam        resist coating (i.e. ridges); and an array of grooves extending        through the eBeam resist pattern layer;        wherein the eBeam resist coating comprises an optionally dried        and/or cured eBeam resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of performing electron-beam lithography, the method comprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate;    -   ii) exposing part(s) of the (eBeam) resist coating to (electron        beam) radiation to provide an exposed (eBeam) resist coating;    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) optionally modifying the substrate, substrate surface, or        part(s) thereof, underlying the (eBeam) resist pattern layer;    -   v) optionally removing the (eBeam) resist pattern layer to        provide a modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (optionally with an alternative resist coating, such        as a photoresist, instead of the eBeam resist coating; and        optionally using alternative radiation during exposure, such as        visible or ultraviolet light, instead of electron beam        radiation) upon the modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) (i.e. pre-steps (i)-(vi)),        optionally repeated one or more times, using either an eBeam        resist coating or an alternative resist coating and using either        electron beam radiation or alternative radiation during        exposure;        wherein the eBeam resist coating comprises an optionally dried        and/or cured eBeam resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided animaged substrate obtainable by, obtained by, or directly obtained by themethod of performing electron-beam lithography as defined herein.

According to a further aspect of the invention, there is provided amethod of selectively modifying a surface of a substrate, the methodcomprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate;    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) selectively modifying the substrate, substrate surface, or        part(s) thereof, underlying the (eBeam) resist pattern layer,    -   v) optionally removing the (eBeam) resist pattern layer to        provide a modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (optionally with an alternative resist coating, such        as a photoresist, instead of the eBeam resist coating; and        optionally using alternative radiation during exposure, such as        visible or ultraviolet light, instead of electron beam        radiation) upon the modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) (i.e. pre-steps (i)-(vi)),        optionally repeated one or more times, using an alternative        resist coating instead of the eBeam resist coating and        optionally using alternative radiation during exposure instead        of electron beam radiation;        wherein the eBeam resist coating comprises an optionally dried        and/or cured (eBeam) resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of manufacturing a lithographic mask (e.g. a photomask), themethod comprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an resist coating to a substrate (suitably a        substrate suitable for use in lithography);    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) optionally selectively modifying the substrate, substrate        surface, or part(s) thereof, underlying the (eBeam) resist        pattern layer (suitably such that the modified part(s) of the        substrate or substrate surface have increased or decreased        transparency to a pre-determined type of radiation, e.g.        radiation used in photolithography, relative to the original        substrate or unmodified part(s) of the substrate or substrate        surface);    -   v) optionally removing the (eBeam) resist pattern layer to        provide a modified substrate;        wherein the eBeam resist coating comprises an optionally dried        and/or cured (eBeam) resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided alithographic mask (e.g. a photomask) obtainable by, obtained by, ordirectly obtained by the method of manufacturing a lithographic mask(e.g. a photomask) defined herein.

According to a further aspect of the invention, there is provided amethod of performing lithography, the method comprising:

-   -   i) providing a resist-coated substrate or applying a resist        coating to a substrate (the resist coating may be any resist        coating suitable for exposing via a lithographic mask, e.g. a        photoresist);    -   ii) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;    -   iii) developing the exposed resist coating to generate a resist        pattern layer, the resist pattern layer comprising:        developer-insoluble coating portions of the resist coating (i.e.        ridges); and an array of grooves extending through the resist        pattern layer;    -   iv) optionally modifying the substrate, substrate surface, or        part(s) thereof, underlying the resist pattern layer;    -   v) optionally removing the resist pattern layer to provide a        modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (with either an eBeam resist coating of the        invention or an alternative resist coating, such as a        photoresist; and optionally using electron beam radiation with        or without a lithographic mask or alternative radiation during        exposure, such as visible or ultraviolet light) upon the        modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) of this method and/or the method of        performing electron-beam lithography (i.e. pre-steps (i)-(vi)),        optionally repeated one or more times, using either an eBeam        resist coating or an alternative resist coating and using either        electron beam radiation or alternative radiation during        exposure.

According to a further aspect of the invention, there is provided animaged substrate obtainable by, obtained by, or directly obtained by themethod of performing lithography as defined herein.

According to a further aspect of the invention, there is provided amethod of manufacturing a multi-layered substrate, the methodcomprising:

-   -   i) providing a resist-coated substrate or applying a resist        coating to a substrate (the resist coating may be any resist        coating suitable for exposing via a lithographic mask, e.g. a        photoresist);    -   ii) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;    -   iii) developing the exposed resist coating to generate a resist        pattern layer, the resist pattern layer comprising:        developer-insoluble coating portions of the resist coating (i.e.        ridges); and an array of grooves extending through the resist        pattern layer;    -   iv) selectively modifying the substrate, substrate surface, or        part(s) thereof, underlying the resist pattern layer,    -   v) removing the resist pattern layer to provide a modified        substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (with either an eBeam resist coating of the        invention or an alternative resist coating, such as a        photoresist; and optionally using electron beam radiation with        or without a lithographic mask or alternative radiation during        exposure, such as visible or ultraviolet light) upon the        modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) of this method and/or of the method        of performing electron-beam lithography (i.e. pre-steps        (i)-(vi)), optionally repeated one or more times, using either        an eBeam resist coating or an alternative resist coating and        using either electron beam radiation or alternative radiation        during exposure; wherein the eBeam resist coating comprises an        optionally dried and/or cured resist composition; wherein the        eBeam resist composition comprises an anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of manufacturing a multi-layered substrate, the methodcomprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate;    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        resist coating (i.e. ridges); and an array of grooves extending        through the (eBeam) resist pattern layer;    -   iv) selectively modifying the substrate, substrate surface, or        part(s) thereof, underlying the (eBeam) resist pattern layer,    -   v) removing the (eBeam) resist pattern layer to provide a        modified substrate;    -   vi) optionally repeating, at least once, step iv) and/or steps        i)-v) (optionally with an alternative resist coating, such as a        photoresist, instead of the eBeam resist coating; and optionally        using alternative radiation during exposure, such as visible or        ultraviolet light, instead of electron beam radiation) upon the        modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) of this method and/or of the method        of performing electron-beam lithography (i.e. pre-steps        (i)-(vi)), optionally repeated one or more times, using either        an eBeam resist coating or an alternative resist coating and        using either electron beam radiation or alternative radiation        during exposure;        wherein the eBeam resist coating comprises an optionally dried        and/or cured resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided amethod of manufacturing a multi-layered substrate, the methodcomprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate; and    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;        -   OR    -   i) providing a resist-coated substrate or applying a resist        coating to a substrate (wherein the resist coating is either as        defined herein or is any alternative resist coating suitable for        exposing via a lithographic mask, e.g. a photoresist); and    -   ii) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;        -   AND    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        resist coating (i.e. ridges); and an array of grooves extending        through the (eBeam) resist pattern layer;    -   iv) selectively modifying the substrate, substrate surface, or        part(s) thereof, underlying the (eBeam) resist pattern layer,    -   v) removing the (eBeam) resist pattern layer to provide a        modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (with either an eBeam resist coating of the        invention or an alternative resist coating, such as a        photoresist; and optionally using electron beam radiation with        or without a lithographic mask or alternative radiation during        exposure, such as visible or ultraviolet light) upon the        modified substrate;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) of this method (i.e. pre-steps        (i)-(vi), optionally using either of the two step (i)/(ii)        combinations) and/or performing steps (i) to (vi) of the method        of performing electron beam lithography, optionally repeated one        or more times, using either an eBeam resist coating or an        alternative resist coating and using either electron beam        radiation or alternative radiation during exposure;        wherein the eBeam resist coating comprises an optionally dried        and/or cured resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided amulti-layered substrate obtainable by, obtained by, or directly obtainedby a method of manufacturing a multi-layered substrate as definedherein.

According to a further aspect of the invention, there is provided amethod of fabricating an integrated circuit die or an integrated circuitwafer comprising a plurality of integrated circuit dice, the or each diecomprising a plurality of electronic components, wherein the methodcomprises:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate; and    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;        -   OR    -   i) providing a resist-coated substrate or applying a resist        coating to a substrate (the resist coating may be any resist        coating suitable for exposing via a lithographic mask, e.g. a        photoresist); and    -   ii) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;        -   AND    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) modifying the substrate, substrate surface, or part(s)        thereof, underlying the (eBeam) resist pattern layer (this may        involve conductively interconnecting the electronic components        of the or each die with conductor(s));    -   v) removing the (eBeam) resist pattern layer to provide a        modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (with either a resist coating of the invention or an        alternative resist coating, such as a photoresist; and        optionally using electron beam radiation with or without a        lithographic mask or alternative radiation during exposure, such        as visible or ultraviolet light) upon the modified substrate;    -   vii) optionally conductively interconnecting the electronic        components of the or each die with conductor(s) (if not already        performed during one or more substrate/substrate-surface        modifying steps) to provide an integrated circuit with external        contact terminals;    -   viii) optionally performing one or more further finishing steps;    -   ix) optionally separating an integrated circuit die from a wafer        comprising a plurality of integrated circuit dice;        wherein step (i) of the method is optionally preceded by        performing steps (i) to (vi) of this method (i.e. pre-steps        (i)-(vi), optionally using either of the two step (i)/(ii)        combinations) and/or performing steps (i) to (vi) of the method        of performing electron beam lithography, optionally repeated one        or more times, using either an eBeam resist coating or an        alternative resist coating and using either electron beam        radiation or alternative radiation during exposure;        wherein the eBeam resist coating comprises an optionally dried        and/or cured resist composition;        wherein the eBeam resist composition comprises an        anti-scattering compound.

According to a further aspect of the invention, there is provided anintegrated circuit die obtainable by, obtained by, or directly obtainedby a method of fabricating an integrated circuit die as defined herein.

According to a further aspect of the invention, there is provided anintegrated circuit wafer comprising a plurality of integrated circuitdice, the integrated circuit wafer being obtainable by, obtained by, ordirectly obtained by a method of fabricating an integrated circuit waferas defined herein.

According to a further aspect of the invention, there is provided amethod of manufacturing an integrated circuit package, the integratedcircuit package comprising a plurality of pins and an integrated circuitdie with external contact terminals conductively connected to thecorresponding plurality of pins, wherein the method comprises:

-   -   i) providing an integrated circuit die as defined herein or        fabricating an integrated circuit die by a method of fabricating        an integrated circuit die as defined herein;    -   ii) attaching the integrated circuit die to a package substrate,        wherein the package substrate comprises electrical contacts,        each of the electrical contacts being optionally connected or        connectable to a corresponding pin;    -   iii) conductively connecting each of the external contact        terminals of the integrated circuit die to corresponding        electrical contacts of the package substrate;    -   iv) optionally (and if necessary) connecting the electrical        contacts of the package substrate to corresponding pins;    -   v) encapsulating the integrated circuit die.

According to a further aspect of the invention, there is provided anintegrated circuit package obtainable by, obtained by, or directlyobtained by a method of manufacturing an integrated circuit package asdefined herein.

According to a further aspect of the invention, there is provided amethod of manufacturing a circuit board comprising an integrated circuitpackage (suitably as defined herein) comprising a plurality of pins,wherein the method comprises:

-   -   i) providing an integrated circuit package as defined herein or        manufacturing an integrated circuit package by a method of        manufacturing an integrated circuit package as defined herein;    -   ii) conductively connecting the integrated circuit package to a        circuit board.

According to a further aspect of the invention, there is provided acircuit board obtainable by, obtained by, or directly obtained by amethod of manufacturing a circuit board as defined herein.

According to a further aspect of the invention, there is provided amethod of manufacturing an electronic device or system, the electronicdevice or system comprising or being connectable to a power source andcomprising a circuit board conductively connected to or connectable to apower source, wherein the method comprises:

-   -   i) providing a circuit board as defined herein or manufacturing        a circuit board by a method of manufacturing a circuit board as        defined herein;    -   ii) incorporating the circuit board within the electronic device        or system.

According to a further aspect of the invention, there is provided anelectronic device or system obtainable by, obtained by, or directlyobtained by a method of manufacturing an electronic device or system asdefined herein

According to a further aspect of the invention, there is provided a useof an eBeam resist composition for coating a substrate with an eBeamresist coating; for patterning a substrate; for imaging; as a resistcoating in electron-beam lithography; for selectively modifying asurface of a substrate; for manufacturing a lithographic mask (such asthose used in performing lithography or the production of integratedcircuits etc.); for manufacturing a multi-layered substrate; forfabricating an integrated circuit die; for fabricating an integratedcircuit wafer; for manufacturing an integrated circuit package; formanufacturing a circuit board; or for manufacturing an electronic deviceor system.

Any features, including optional, suitable, and preferred features,described in relation to any particular aspect of the invention may alsobe features, including optional, suitable and preferred features, of anyother aspect of the present invention.

In addition to its use with electron beam technology, the presentinvention is also suitably applicable to other particulate radiationsystems, for instance, systems which utilize ion beams such as focusedion beams (FIB) or proton beams (e.g. as in proton beam writing, PBW).As such, in any of the aforesaid aspects of the invention where electronbeam radiation is used, an ion beam (such as a focused ion beam orproton beam) may be used instead. As such, all references herein toeBeam and electron beams may be taken, in alternative aspects of theinvention, to relate to ion beams.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how embodimentsof the same are put into effect, reference is now made, by way ofexample, to the following diagrammatic drawings, in which:

FIG. 1 is a chart showing the number of Secondary Electrons generated ina 100 nm thick films at 30 KeV eBeam exposure for compounds of molecularweights shown as a function of density.

FIG. 2 is a chart showing a close up of FIG. 1, where the moleculeweight is varied from 10000 to 16000 g/mol. All conditions are the sameas FIG. 1.

FIG. 3 shows SEM images illustrating: a) 50 nm lines exposed in PMMAwith a dose of 774 pC/cm. The sample was developed with MIBK:IPA withthe ratio of 1:3. b) 6.22 nm lines exposed in GW20-14 with a dose of6200 pC/cm. The sample was developed with Hexane.

FIG. 4 is a chart showing the internal electron scattering interactionsinside the Nickel Chromium ring like structured materials exposed to anacceleration voltage of 30 KeV. Secondary electrons and backscatteredelectrons are indicated in Red and Blue respectively.

FIG. 5 shows SEM images illustrating: (a) Profile view of 6.22 nm lineson a 200 nm pitch (tilt 70°). (b) Profile view of 10.4 nm lines on a 100nm pitch (tilt 70°). Dose is 6200 pC/cm.

FIG. 6 shows an SEM image illustrating a profile view of 16.3 nm lineson a 200 nm pitch (tilt 70°). Dose is 6000 pC/cm.

FIG. 7 shows an SEM image of GT188-13 material illustrating a profileview of 13.9 nm lines on a 200 nm pitch (tilt 70°). Dose is 16850 pC/cm.

FIG. 8 shows an SEM image of the GT133-14 material illustrating aprofile view of 26.1 nm lines on a 200 nm pitch (tilt 70°). Dose is 1000pC/cm.

FIG. 9 is a chart showing Resolution and Aspect ratio of eachantiscattering compound with a 200 nm pitch.

FIG. 10 is a chart showing the internal electron scattering interactionsinside GW20-14 using 30 KeV acceleration voltage. Secondary electronsand backscattered electrons are indicated in Red and Blue respectively.

FIG. 11 is a chart showing the number of Secondary Electrons generatedin a 100 nm thick GW20-14 film.

FIG. 12 shows SEM images illustrating (a) Profile view of 6.22 nm lineson a 200 nm pitch (tilt 70°). (b) Profile view of 10.4 nm lines on a 100nm pitch (tilt 70°).

FIG. 13 is a chart showing the internal electron scattering interactionsinside (a) GW20-14 that had a 7.5 nm nanostructure with a 200 nm pitchand had a dose of 6200 pC/cm, (b) GW20-14 that has a 10 nm nanostructurewith a 100 nm pitch and has a dose of 9950 pC/cm. Secondary electronsand backscattered electrons are indicated in Red and Blue respectively.

FIGS. 14.1-14.11 are SEM images showing various lines written usingeBeam in the various eBeam resist compositions.

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless otherwise stated, the following terms used in the specificationand claims have the following meanings set out below.

Herein, unless stated otherwise, the terms “radiation” and “irradiation”refer to the exposure of the resist composition, or coating thereof, toradiation that causes a physical or chemical change in the resistcomposition thereby allowing it to be “developed”. The radiation inquestion may be any suitable radiation. Where electron-beam lithographyis being performed, the radiation is electron beam radiation, but sincethe present invention allows multiple resist compositions to be used,for instance during the formation of multi-layered integrated circuits,some of the resist compositions may be other than eBeam resistcompositions of the invention and may instead be visible/UV photoresistsor such like where the relevant radiation is visible/ultravioletradiation (e.g. suitably for use in photolithography).

Herein, a “base polymeric component”, a “resist component”, or a “resistpolymer” in a resist composition is a component which undergoes a changeupon exposure to the relevant radiation (e.g. electron beam radiation,ionizing radiation, ultraviolet radiation). The resist component ofresist compositions of the invention (for use with eBeam lithography)comprises an anti-scattering compound, but may additionally compriseother resist components, such as a polymeric component (suitably apolymeric resin—e.g. PMMA). Where resist compositions excluded from thescope of the invention are used, such compositions may comprise suchother resist components, including a polymeric component, and mayoptionally be (substantially) free of an anti-scattering compound.

Herein, unqualified references to a “resist composition”, “resistcoating”, “resist material”, “resist-coated material”, etc. may relateto an eBeam resist composition, coating, material, or coated material ofthe invention, or may relate to an alternative resist composition,coating, material, or coated material, which may include eBeam resistsexcluded from the scope of the invention or non-eBeam resists (e.g.photoresists). Most preferably, an unqualified reference to a resistcomposition, coating, material, or coated material refers to analternative resist, suitably a non-eBeam alternative resist, mostsuitably a photoresist. Such alternative resists are especiallyappropriate for pre-steps (i.e. before an eBeam resist composition ofthe invention is used or before a tool generated using an eBeam resistcomposition of the invention is used, e.g. a lithographic mask of theinvention), repeat steps (e.g. when producing multi-layered substrate)where alternative resists may be used before or after using eBeamresists of the invention (lithographic masks obtained by using eBeamresists of the invention), or in lithographic steps involvinglithographic masks (especially where said lithographic masks arethemselves produced by the methods of the invention). In a particularembodiment a photomask, produced using the resists and electron beamexposure methods of the invention, may be employed in photolithography.Such use still takes advantage of the benefits afforded by the presentinvention since the photomasks may include ultra high-resolution detailnot typically obtainable, thereby allowing for ultra high-resolutionphotolithography. Crucially, methods of the invention involve at leastone step where an eBeam resist composition or coating of the inventionis used or at least one step where a tool (e.g. lithographic mask) ofthe invention is used. However, such methods may involve a multiplicityof other steps which do not employ either the eBeam resist compositionor coating of the invention nor a tool produced therefrom (e.g.integrated circuits may be produced using 100s of steps, but suchproduction will fall within the scope of the invention where resistcompositions/coatings or tools of the invention are used in at least onestep). It is well within the skilled person's common general knowledgeto perform method steps using resists and lithographic masks outside thescope of the invention.

“Alternative resist compositions” and coatings may be produced and usedin accordance with standard workshop techniques well known to thoseskilled in the art. They may also be used in the same manner as definedherein in relation to eBeam resist compositions and coatings of theinvention (including methods of coating, exposing, developing, removing,etc.), though the skilled person could readily adapt the methods definedherein to suit the alternative resists in question.

Herein “an anti-scattering compound” (which may in some cases be aresist component in itself) within an eBeam resist composition suitablyserves to temper and control the impact of incident radiation (andoptionally also secondary electrons) on resist patterning. Theanti-scattering compound is thought to help focus and direct incidentradiation (and/or secondary electrons, where they are produced) to thedesired exposure sites, to thereby minimize any undesired exposure. Thisin turn allows for a much sharper, higher resolution image to bepatterned within the resists in question. Moreover, the anti-scatteringcompound can prevent or reduce over-exposure of certain vulnerablecomponents within the resist, which may otherwise compromise subsequentdeveloping of the exposed resist. The anti-scattering compound thereforeallows reduced blurring; reduce proximity effects (i.e. spillage ofenergy to otherwise unexposed parts of the resist); increasedresolution, and increased aspect ratio (where aspect ratio is the depthdivided by the width of the relevant pattern lines, whether grooves orridges). Where an anti-scattering compound is described as containingone or more complexes whose charges do not cancel (to give a neutralcompound), the actual antiscattering compound is a suitable salt of thenon-neutral combination of complexes (thus giving a neutral compoundoverall). The skilled person will well understand that any remainingcharges will generally be neutralised by appropriate countercations orcounteranions. As such, throughout this specification the antiscatteringcompounds, and indeed any complexes, may be defined without saidcounterions.

Herein, the term “developer-insoluble” is intended to denote that agiven coating portion has a relatively lower solubility in a developerthan corresponding “developer-soluble” coating portions. It does notnecessarily exclude where “developer-insoluble” coating portions havepartial or even full solubility (if development times were sufficientlylong) in a developer. As will be appreciated by those skilled in theart, coating portions are differentially designated as“developer-soluble” and “developer-insoluble” to indicate that parts ofthe coating (e.g. radiation-exposed parts) have different solubilityproperties, and thus typically a different chemical nature, to otherparts of the coating (e.g. non-radiation-exposed parts). The nature ofthe developer is immaterial since this can be judiciously selected,depending on which portions of coating are intended for removal, on thebasis of the differential solubility properties of the respectivecoating portions. Generally speaking, the term “solubility”, as used inthe context of developing, relates to kinetic solubility rather thanthermodynamic solubility, since the speed of solubilisation is keythough thermodynamic solubility may correlate with kinetic solubility,as would be understood by the skilled person.

In general, use of the terms “(eBeam) resist coating” and “(electronbeam) radiation” in methods of the invention denote that an eBeam resistcoating of the invention and electron beam radiation is used in saidmethod at least once, but that alternative resist coating(s) andalternative radiation may optionally be used instead in one, some, orall of any other steps (e.g. repeat steps and/or pre-steps). Where, asin some methods of the invention, reference is made to optional repeatsteps or pre-steps that involve “performing steps (i) to (vi) of themethod of performing electron beam lithography”, in this contextperformance of the method of performing electron beam lithography mayoptionally exclusively involve alternative resist coatings andalternative radiation instead of eBeam resist coatings of the inventionan electron beam radiation—i.e. in this context reference to the methodof performing electron beam lithography is merely a shorthand for repeator pre-steps that may involve either eBeam resists of the invention oralternative resists.

Unless stated otherwise, any reference herein to an “average” value isintended to relate to the mean value.

Herein, unless stated otherwise, the term “parts by weight” (pbw) whenused in relation to multiple ingredients/components, refers to relativeratios between said multiple ingredients/components. Though in manyembodiments the amounts of individual components within a compositionmay be given as a “wt %” value, in alternative embodiments any or allsuch wt % values may be converted to parts by weight to define amulti-component composition. This is so because the relative ratiosbetween components is often more important than the absoluteconcentrations thereof. Where a composition comprising multipleingredients is described in terms of parts by weight alone (i.e. toindicate only relative ratios of ingredients), it is not necessary tostipulate the absolute amounts or concentrations of said ingredients(whether in toto or individually) because the advantages of theinvention stem from the relative ratios of the respective ingredientsrather than their absolute quantities or concentrations. However,suitably, the resist composition comprises at least 1 wt % of all thestipulated ingredients combined (excluding any diluents/solvents),suitably at least 5 wt %, suitably at least 10 wt %, suitably at least15 wt %. Suitably the resist composition comprises at most 50 wt % ofall the stipulated ingredients combined (excluding anydiluents/solvents), suitably at most 30 wt %, suitably at most 20 wt %thereof. The balance (i.e. the remainder of the resist composition notconstituted by the stipulated ingredients, excluding diluents/solvents)may consist essentially of a diluent(s)/solvent(s).

Herein, references to a “complex”, such as a metal complex (e.g. primarymetal complex) or co-ordination complex, will be well understood bythose skilled in the art (especially in inorganic chemistry). Herein,complexes generally involve one or more metal species (generally metalions) co-ordinated to one or more ligands. Where a particular complex isdefined by reference to a formula and/or a list of components, unlessstated otherwise, suitably such a complex may include any salt, solvate,or hydrate thereof and may additionally or alternatively include one ormore optional extra/terminal ligands, and/or one or more additionalmetal species. In most embodiments, any defined complex may suitablyinclude a salt thereof (especially where the complex has a net charge).Suitably, however, such a complex may be (substantially) as specificallydefined (notwithstanding the optional salt form), i.e. may exclude asolvate, hydrate, or complex with one or more optional extra/terminalligands, and/or one or more additional metal species. Moreover, where aparticular complex is defined by a formula and/or a list of components,and absolute or relative amounts of the individual species of thecomplex are given (e.g. whether by reference to stoichiometry or molesof a species per mole of complex), unless stated otherwise this maysuitably include any variants in which the absolute or relative amountsof the individual species are within +/−10% of those stipulated, moresuitably within +/−5%, more suitably within +/−1%, more suitably within+/−0.1%, though in preferred embodiments the complex, including anyabsolute or relative amounts of individual species of the complex, is(substantially) as defined.

Herein, an unspecified number of a plurality of species of type X (e.g.be it a metal species, a ligand species, etc.) may be referred to as X₁,X₂, . . . , X_(n), or in the context of a complex may be stipulated as[X₁X₂ . . . X_(n)], where X₁ is the first species of type X, X₂ is thesecond species of type X, and X_(n) is the nth species of type X (e.g.X₃, X₄, . . . ).

Herein, unless stated otherwise, all chemical nomenclature may bedefined in accordance with IUPAC definitions.

In this specification the term “alkyl” includes both straight andbranched chain alkyl groups. References to individual alkyl groups suchas “propyl” are specific for the straight chain version only andreferences to individual branched chain alkyl groups such as “isopropyl”are specific for the branched chain version only. For example,“(1-6C)alkyl” includes (1-4C)alkyl, (1-3C)alkyl, propyl, isopropyl andt-butyl. A similar convention applies to other radicals, for example“phenyl(1-6C)alkyl” includes phenyl(1-4C)alkyl, benzyl, 1-phenylethyland 2-phenylethyl.

The term “(m-nC)” or “(m-nC) group” used alone or as a prefix, refers toany group having m to n carbon atoms. In embodiments stipulating a valuefor n that is greater than or equal to 6, n may optionally be a smallernumber, for instance n may be 2, 4, or 5.

An “alkylene,” “alkenylene,” or “alkynylene” group is an alkyl, alkenyl,or alkynyl group that is positioned between and serves to connect twoother chemical groups. Thus, “(1-6C)alkylene” means a linear saturateddivalent hydrocarbon radical of one to six carbon atoms or a branchedsaturated divalent hydrocarbon radical of three to six carbon atoms, forexample, methylene, ethylene, propylene, 2-methylpropylene, pentylene,and the like.

“(2-6C)alkenylene” means a linear divalent hydrocarbon radical of two tosix carbon atoms or a branched divalent hydrocarbon radical of three tosix carbon atoms, containing at least one double bond, for example, asin ethenylene, 2,4-pentadienylene, and the like.

“(2-6C)alkynylene” means a linear divalent hydrocarbon radical of two tosix carbon atoms or a branched divalent hydrocarbon radical of three tosix carbon atoms, containing at least one triple bond, for example, asin ethynylene, propynylene, and butynylene and the like.

“(3-8C)cycloalkyl” means a hydrocarbon ring containing from 3 to 8carbon atoms, for example, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl or bicyclo[2.2.1]heptyl.

“(3-8C)cycloalkenyl” means a hydrocarbon ring containing at least onedouble bond, for example, cyclobutenyl, cyclopentenyl, cyclohexenyl orcycloheptenyl, such as 3-cyclohexen-1-yl, or cyclooctenyl.

“(3-8C)cycloalkyl-(1-6C)alkylene” means a (3-8C)cycloalkyl groupcovalently attached to a (1-6C)alkylene group, both of which are definedherein.

The term “halo” refers to fluoro, chloro, bromo and iodo.

The term “heterocyclyl”, “heterocyclic” or “heterocycle” means anon-aromatic saturated or partially saturated monocyclic, fused,bridged, or spiro bicyclic heterocyclic ring system(s). The termheterocyclyl includes both monovalent species and divalent species.Monocyclic heterocyclic rings contain from about 3 to 12 (suitably from3 to 7) ring atoms, with from 1 to 5 (suitably 1, 2 or 3) heteroatomsselected from nitrogen, oxygen or sulfur in the ring. Bicyclicheterocycles contain from 7 to 17 member atoms, suitably 7 to 12 memberatoms, in the ring. Bicyclic heterocycles contain from about 7 to about17 ring atoms, suitably from 7 to 12 ring atoms. Bicyclicheterocyclic(s) rings may be fused, spiro, or bridged ring systems.Examples of heterocyclic groups include cyclic ethers such as oxiranyl,oxetanyl, tetrahydrofuranyl, dioxanyl, and substituted cyclic ethers.Heterocycles containing nitrogen include, for example, azetidinyl,pyrrolidinyl, piperidinyl, piperazinyl, tetrahydrotriazinyl,tetrahydropyrazolyl, and the like. Typical sulfur containingheterocycles include tetrahydrothienyl, dihydro-1,3-dithiol,tetrahydro-2H-thiopyran, and hexahydrothiepine. Other heterocyclesinclude dihydro-oxathiolyl, tetrahydro-oxazolyl, tetrahydro-oxadiazolyl,tetrahydrodioxazolyl, tetrahydro-oxathiazolyl, hexahydrotriazinyl,tetrahydro-oxazinyl, morpholinyl, thiomorpholinyl,tetrahydropyrimidinyl, dioxolinyl, octahydrobenzofuranyl,octahydrobenzimidazolyl, and octahydrobenzothiazolyl. For heterocyclescontaining sulfur, the oxidized sulfur heterocycles containing SO or SO₂groups are also included. Examples include the sulfoxide and sulfoneforms of tetrahydrothienyl and thiomorpholinyl such as tetrahydrothiene1,1-dioxide and thiomorpholinyl 1,1-dioxide. A suitable value for aheterocyclyl group which bears 1 or 2 oxo (═O) or thioxo (═S)substituents is, for example, 2-oxopyrrolidinyl, 2-thioxopyrrolidinyl,2-oxoimidazolidinyl, 2-thioxoimidazolidinyl, 2-oxopiperidinyl,2,5-dioxopyrrolidinyl, 2,5-dioxoimidazolidinyl or 2,6-dioxopiperidinyl.Particular heterocyclyl groups are saturated monocyclic 3 to 7 memberedheterocyclyls containing 1, 2 or 3 heteroatoms selected from nitrogen,oxygen or sulfur, for example azetidinyl, tetrahydrofuranyl,tetrahydropyranyl, pyrrolidinyl, morpholinyl, tetrahydrothienyl,tetrahydrothienyl 1,1-dioxide, thiomorpholinyl, thiomorpholinyl1,1-dioxide, piperidinyl, homopiperidinyl, piperazinyl orhomopiperazinyl. As the skilled person would appreciate, any heterocyclemay be linked to another group via any suitable atom, such as via acarbon or nitrogen atom. However, reference herein to piperidino ormorpholino refers to a piperidin-1-yl or morpholin-4-yl ring that islinked via the ring nitrogen.

By “bridged ring systems” is meant ring systems in which two rings sharemore than two atoms, see for example Advanced Organic Chemistry, byJerry March, 4^(th) Edition, Wiley Interscience, pages 131-133, 1992.Examples of bridged heterocyclyl ring systems include,aza-bicyclo[2.2.1]heptane, 2-oxa-5-azabicyclo[2.2.1]heptane,aza-bicyclo[2.2.2]octane, aza-bicyclo[3.2.1]octane and quinuclidine.

“Heterocyclyl(1-6C)alkyl” means a heterocyclyl group covalently attachedto a (1-6C)alkylene group, both of which are defined herein.

The term “heteroaryl” or “heteroaromatic” means an aromatic mono-, bi-,or polycyclic ring incorporating one or more (for example 1-4,particularly 1, 2 or 3) heteroatoms selected from nitrogen, oxygen orsulfur. The term heteroaryl includes both monovalent species anddivalent species. Examples of heteroaryl groups are monocyclic andbicyclic groups containing from five to twelve ring members, and moreusually from five to ten ring members. The heteroaryl group can be, forexample, a 5- or 6-membered monocyclic ring or a 9- or 10-memberedbicyclic ring, for example a bicyclic structure formed from fused fiveand six membered rings or two fused six membered rings. Each ring maycontain up to about four heteroatoms typically selected from nitrogen,sulfur and oxygen. Typically the heteroaryl ring will contain up to 3heteroatoms, more usually up to 2, for example a single heteroatom. Inone embodiment, the heteroaryl ring contains at least one ring nitrogenatom. The nitrogen atoms in the heteroaryl rings can be basic, as in thecase of an imidazole or pyridine, or essentially non-basic as in thecase of an indole or pyrrole nitrogen. In general the number of basicnitrogen atoms present in the heteroaryl group, including any aminogroup substituents of the ring, will be less than five.

Examples of heteroaryl include furyl, pyrrolyl, thienyl, oxazolyl,isoxazolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxadiazolyl,thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyridazinyl, pyrimidinyl,pyrazinyl, 1,3,5-triazenyl, benzofuranyl, indolyl, isoindolyl,benzothienyl, benzoxazolyl, benzimidazolyl, benzothiazolyl,benzothiazolyl, indazolyl, purinyl, benzofurazanyl, quinolyl,isoquinolyl, quinazolinyl, quinoxalinyl, cinnolinyl, pteridinyl,naphthyridinyl, carbazolyl, phenazinyl, benzisoquinolinyl,pyridopyrazinyl, thieno[2,3-b]furanyl, 2H-furo[3,2-b]-pyranyl,5H-pyrido[2,3-d]-o-oxazinyl, 1H-pyrazolo[4,3-d]-oxazolyl,4H-imidazo[4,5-d]thiazolyl, pyrazino[2,3-d]pyridazinyl,imidazo[2,1-b]thiazolyl, imidazo[1,2-b][1,2,4]triazinyl. “Heteroaryl”also covers partially aromatic bi- or polycyclic ring systems wherein atleast one ring is an aromatic ring and one or more of the other ring(s)is a non-aromatic, saturated or partially saturated ring, provided atleast one ring contains one or more heteroatoms selected from nitrogen,oxygen or sulfur. Examples of partially aromatic heteroaryl groupsinclude for example, tetrahydroisoquinolinyl, tetrahydroquinolinyl,2-oxo-1,2,3,4-tetrahydroquinolinyl, dihydrobenzthienyl,dihydrobenzfuranyl, 2,3-dihydro-benzo[1,4]dioxinyl, benzo[1,3]dioxolyl,2,2-dioxo-1,3-dihydro-2-benzothienyl, 4,5,6,7-tetrahydrobenzofuranyl,indolinyl, 1,2,3,4-tetrahydro-1,8-naphthyridinyl,1,2,3,4-tetrahydropyrido[2,3-b]pyrazinyl and3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazinyl

Examples of five membered heteroaryl groups include but are not limitedto pyrrolyl, furanyl, thienyl, imidazolyl, furazanyl, oxazolyl,oxadiazolyl, oxatriazolyl, isoxazolyl, thiazolyl, isothiazolyl,pyrazolyl, triazolyl and tetrazolyl groups.

Examples of six membered heteroaryl groups include but are not limitedto pyridyl, pyrazinyl, pyridazinyl, pyrimidinyl and triazinyl.

A bicyclic heteroaryl group may be, for example, a group selected from:

a benzene ring fused to a 5- or 6-membered ring containing 1, 2 or 3ring heteroatoms;

a pyridine ring fused to a 5- or 6-membered ring containing 1, 2 or 3ring heteroatoms;

a pyrimidine ring fused to a 5- or 6-membered ring containing 1 or 2ring heteroatoms;

a pyrrole ring fused to a 5- or 6-membered ring containing 1, 2 or 3ring heteroatoms;

a pyrazole ring fused to a 5- or 6-membered ring containing 1 or 2 ringheteroatoms;

a pyrazine ring fused to a 5- or 6-membered ring containing 1 or 2 ringheteroatoms;

an imidazole ring fused to a 5- or 6-membered ring containing 1 or 2ring heteroatoms;

an oxazole ring fused to a 5- or 6-membered ring containing 1 or 2 ringheteroatoms;

an isoxazole ring fused to a 5- or 6-membered ring containing 1 or 2ring heteroatoms;

a thiazole ring fused to a 5- or 6-membered ring containing 1 or 2 ringheteroatoms;

an isothiazole ring fused to a 5- or 6-membered ring containing 1 or 2ring heteroatoms;

a thiophene ring fused to a 5- or 6-membered ring containing 1, 2 or 3ring heteroatoms;

a furan ring fused to a 5- or 6-membered ring containing 1, 2 or 3 ringheteroatoms;

a cyclohexyl ring fused to a 5- or 6-membered heteroaromatic ringcontaining 1, 2 or 3 ring heteroatoms; and

a cyclopentyl ring fused to a 5- or 6-membered heteroaromatic ringcontaining 1, 2 or 3 ring heteroatoms.

Particular examples of bicyclic heteroaryl groups containing a sixmembered ring fused to a five membered ring include but are not limitedto benzfuranyl, benzthiophenyl, benzimidazolyl, benzoxazolyl,benzisoxazolyl, benzthiazolyl, benzisothiazolyl, isobenzofuranyl,indolyl, isoindolyl, indolizinyl, indolinyl, isoindolinyl, purinyl(e.g., adeninyl, guaninyl), indazolyl, benzodioxolyl andpyrazolopyridinyl groups.

Particular examples of bicyclic heteroaryl groups containing two fusedsix membered rings include but are not limited to quinolinyl,isoquinolinyl, chromanyl, thiochromanyl, chromenyl, isochromenyl,chromanyl, isochromanyl, benzodioxanyl, quinolizinyl, benzoxazinyl,benzodiazinyl, pyridopyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl,phthalazinyl, naphthyridinyl and pteridinyl groups.

“Heteroaryl(1-6C)alkyl” means a heteroaryl group covalently attached toa (1-6C)alkylene group, both of which are defined herein. Examples ofheteroaralkyl groups include pyridin-3-ylmethyl,3-(benzofuran-2-yl)propyl, and the like.

The term “aryl” means a cyclic or polycyclic aromatic ring having from 5to 12 carbon atoms. The term aryl includes both monovalent species anddivalent species. Examples of aryl groups include, but are not limitedto, phenyl, biphenyl, naphthyl and the like. In particular embodiment,an aryl is phenyl.

The term “aryl(1-6C)alkyl” means an aryl group covalently attached to a(1-6C)alkylene group, both of which are defined herein. Examples ofaryl-(1-6C)alkyl groups include benzyl, phenylethyl, and the like.

This specification also makes use of several composite terms to describegroups comprising more than one functionality. Such terms will beunderstood by a person skilled in the art. For exampleheterocyclyl(m-nC)alkyl comprises (m-nC)alkyl substituted byheterocyclyl.

The term “optionally substituted” refers to either groups, structures,or molecules that are substituted and those that are not substituted.

Where optional substituents are chosen from “one or more” groups it isto be understood that this definition includes all substituents beingchosen from one of the specified groups or the substituents being chosenfrom two or more of the specified groups. Suitably examples for optionalsubstituents include, though are not necessarily limited to, halide,amino, cyano, imino, enamino, (1-6C)alkylamino, di-[(1-6C)alkyl]amino,tri-[(1-6C)alkyl]amino, oxo, oxide, hydroxide (OH⁻), (1-6C)alkoxide,(2-6C)alkenyloxy, (2-6C)alkynyloxy, formyl, carboxy,(1-6C)alkoxycarbonyl, (2-6C)alkanoyl, (2-6C)alkanoyloxy, sulpho,sulphide, hydrogensulphide, (1-6C)alkylthio, (2-6C)alkenylthio,(2-6C)alkynylthio, thiocarbonyl, heterocyclyl containing at least oneinternal heteroatom selected from nitrogen, oxygen or sulphur,heteroaryl containing at least one internal hetero atom selected fromnitrogen, oxygen or sulphur (e.g. pyridyl), or (where appropriate);wherein any CH, CH₂, or CH₃ is optionally substituted.

Unless stated otherwise, references herein to a “pKa” should beconstrued as a pKa value in water at standard ambient temperature andpressure (SATP), suitably of the conjugate acid of the relevant species.

Herein, the term “carbocyclyl”, “carbocycle” or “carbocyclic” refers toa radical of a non-aromatic cyclic hydrocarbon group, generally havingfrom 3 to 10 ring carbon atoms (i.e. (3-10C)carbocyclyl) and zeroheteroatoms in the non-aromatic ring system. Suitably, carbocyclylgroups include (3-nC)cycloalkyl and (3-nC)cycloalkenyl. Exemplaryembodiments include: cyclobutyl, cyclobutenyl, cyclopentyl,cyclopentenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, cycloheptyl,cycloheptenyl, cycloheptadienyl, cycloheptatrienyl, cyclooctyl,cyclooctenyl, bicyclo[2.2.1]heptanyl, bicyclo[2.2.2]octanyl, and thelike.

Herein, the term “macrocyclyl”, “macrocycle” or “macrocyclic” refers tomacrocyclic rings, which are well known in the art. Such macrocyclcicrings are suitably cyclic macromolecules or a macromolecular cyclicportions of a molecule. Suitably a macrocyclic ring has nine or moreatoms within the ring. Suitably a macrocyclic ring has three or moreinternal electron-pair donating atoms. A macrocyclic ring is suitably acyclic molecule able to co-ordinate to a central metal species (e.g.Mg²⁺). Examples include porphyrins.

Herein, the term “hydrocarbyl” general refers any aliphatic, acyclic, orcyclic (including aryl) hydrocarbon group, suitably with no heteroatoms.

Herein, a “co-ordinating moiety” is suitably an atom or moiety which iscapable of co-ordinating, suitably through dative bonding, with anotherwise separate atom, molecule, ion, or complex. Suitably aco-ordinating moiety is capable of accepting or donating one or morelone pair of electrons, though suitably a co-ordinating moiety is notcapable of both accepting and donating.

Herein, a “polymetallic” system (e.g. a polymetallic cage) simply meansa system (or complex) having more than one metal atom/ion therein, whichmay be the same or different (in terms of metal element, oxidationstate, etc.). For instance, a metal complex comprising eight Cr(III)ions is polymetallic, as is a metal complex comprising seven Cr(III)ions and one Ni(II) ion. Polymetallic systems, such as a polymetalliccages, may be either homometallic (e.g. where all metal species arederived of the same metal element, even if some metal species have adifferent oxidation state to another) or heterometallic (e.g. where themetal species are a mixture of different metal species derived from adifferent metal element, whether or not the different metal species havethe same or a different oxidation state). Most suitably, all the metalspecies of a homometallic complex are of the same oxidation state,though they may also have different oxidation states. Most suitably,different metal species within a heterometallic complex have a differentoxidation state, though they may also have the same oxidation state.

Herein, a “secondary electron generator” is a component which releasessecondary electrons following irradiation, suitably with ionizingradiation. In a particular embodiment, the secondary electron generatorreleases electrons when exposed to an electron beam.

Herein, the “effective atomic number (Z_(eff))” of a compound is theaverage atomic number obtained from a weighted summation of the atomicconstituents of a compound.

Though the skilled person will be aware of a variety of ways tocalculate and/or measure Z_(eff)(e.g. F. W. Spiers, Effective AtomicNumber and Energy Absorption in Tissues, Br. J. radiol., 19, 52, 1946),for the purpose of the present invention “effective atomic number(Z_(eff))” is suitably calculated as a simple mass-weighted average,suitably using the formula:

Z _(eff)=Σα_(i) Z _(i)

where Z_(i) is the atomic number of the ith element in the compound, andα_(i) is the fraction of the sum total of the atomic numbers of allatoms in the compound (i.e. the total number of protons in the compound)constituted by said ith element. This formula may otherwise be expressedas:

Z _(eff)=α₁ Z ₁+α₂ Z ₂+ . . . (+α_(n) Z _(n))

for a compound comprising n elements.This is similar to the Spiers equation (F. W. Spiers, Effective AtomicNumber and Energy Absorption in Tissues, Br. J. radiol., 19, 52, 1946)but without the exponents used by Spiers. The Spiers equation statesZ_(eff) as follows:

Z _(eff) ^(p)=Σα_(i) Z _(i) ^(p)

where the exponent p is suitably approximately 3 (e.g. p=2.94). Thoughin certain embodiments, this Spiers definition (especially with p=2.94)of Z_(eff) may be used, and any preferred, optional, and suitable valuesof Z_(eff) disclosed herein may equally apply to the Spiers definition,preferably the above mentioned simple mass-weighted average definitionof Z_(eff) should be used.The anti-scattering compound may suitably be or comprise a compoundhaving an effective atomic number (Z_(eff)) less than or equal to 10(optionally when the effective atomic number calculation excludes anysolvates having a boiling point less than or equal to 150° C. at 100 kPapressure).By way of example, the Z_(eff) of PMMA (or methylmethacrylate) isapproximately ˜5.85. Likewise, though not generally relevant to thepresent invention, the effective atomic number of compound mixtures orcompositions may also be calculated by including weighted averages ofthe respective components thereof. The skilled person is perfectlycapable of calculating the effective atomic number (Z_(eff)) for allcompounds and compositions.

Co-pending application PCT/GB2015/050884 (filed on 24 Mar. 2015 by thesame Applicants as the present application), which is herebyincorporated by reference, describes in detail how Z_(eff) may becalculated. For the purpose of the present invention, wherever ananti-scattering agent/compound/complex is associated with a secondaryelectron generator, whether as part of the same composition or event aspart of the same complex, suitably their respective Z_(eff) values aretreated separately. Suitably the anti-scattering agent has verydifferent Z_(eff) and indeed density properties to any correspondingsecondary electron generator, though the combination can be mutuallycomplementary. However, for the purposes of definitions, it may beimportant to segregate parameters such as Z_(eff), density, and suchlike, especially where ideal values and trends run in opposingdirections.

Wherever groups with large carbon chains are disclosed (e.g.(1-12C)alkyl, (1-8C)alkenyl, etc.), such groups may optionally beshorted, for instance containing a between 1 and 5 carbons (e.g.(1-5C)alkyl or (1-5C)alkenyl), or contain between 1 and 3 carbons (e.g.(1-3C)alkyl or (1-3C)alkenyl instead of (1-12C)alkyl or (1-8C)alkenyl).

Herein, unless stated otherwise, the weight percentage (wt %) of anygiven component within a composition suitably means the percentage byweight of said component based on the overall weight of the composition.

Herein, the term “consist essentially of”, when used to describe theproportion of a given ingredient within a material, suitably means thematerial comprises at least 70 wt % of the given ingredient, moresuitably at least 80 wt %, more suitably at least 90 wt %, more suitablyat least 95 wt %, and most suitably at least 99 wt %.

Herein, the term “hydrocarbyl” refers to any hydrocarbon radical,including but not limited to alkyl, alkenyl, alkynyl, aryl.

When stipulated herein (usually in relation to Lewis acidic species),references to a metal atom, species, complex, or compound may include aboron and/or silicon metal atom, species, complex, or compound, eventhough boron and silicon are not strictly metal species as such.However, such metal atoms, species, complexes, or compounds may excludecorresponding boron and/or silicon atoms, species, complexes, orcompounds.

General Methodology and Advantages of the Invention

The present invention provides resist compositions, such as eBeam resistcompositions (whether positive or negative tone resist), which provideaccess to enhanced quality resist patterns deployable in the productionof high-precision, high-specification electronic components (e.g. as perthose present in integrated circuits). In particular, the quality andresolution of the imaged resist patterns facilitates production ofextremely high quality, high resolution electronic components andintegrated circuits, which in turn allows the size of integratedcircuits to be reduced yet further. This in turn paves the way to evenfaster microprocessors and microprocessors that can operate withinlow-power mobile devices.

The deliberate inclusion of an anti-scattering compound within an eBeamresist composition prevents, inhibits, or reduces the generation ofsecondary electrons. In so doing, proximity effects and blurring areminimised, thus allowing for higher resolution patterning. It alsopermits the use of very thin resist film layers.

This disclosure equips the skilled person to judiciously selectappropriate resist compositions and methodologies to optimise theultimate product. The examples and data provided herein, in conjunctionwith the validated predictive models, provide a highly credibledemonstration of the broad applicability of the invention to a range ofresist compositions.

The technology of the present invention may be adapted for use witheither positive or negative tone resists since, generally speaking, apositive resist can be modified to produce a negative resist bytechniques well known in the art (e.g. adding a cross-linking agent).

eBeam Resist Composition

The present invention provides an eBeam resist composition as definedherein, which suitably comprises an anti-scattering compound (suitablyas defined herein). The eBeam resist composition may comprise one ormore anti-scattering compounds as defined herein, in various ratios.

The eBeam resist composition is an electron beam resist composition(i.e. “eBeam resist”).

The anti-scattering compound suitably functions as an electron controlagent, which focuses primary electrons (from electron beams) towardstheir target, suitably whilst minimising proximity effects and/orblurring, suitably whilst minimising generation of secondary electrons.

Suitably the anti-scattering compound causes minimal forward- orback-scattering of electrons when exposed to electron beam radiation.

The eBeam resist composition may optionally comprise a base polymericcomponent (or a resist polymer) as defined herein. Such a base polymericcomponent may be any suitable resist polymer, especially a resistpolymer suitable for use in electron beam lithography (e.g.poly(methylmethacrylate-PMMA). In such embodiments, the eBeam resistcomposition suitably comprises at least 1 pbw (parts by weight)anti-scattering compound per 100 pbw of any base polymeric component(i.e. greater than or equal to 1 pbw anti-scattering compound per 100pbw resist polymer), suitably at least 2 pbw, suitably at least 10 pbw,suitably at least 20 pbw, suitably at least 50 pbw. However, suitablythe anti-scattering compound may itself serve as a resist material,especially where the exposure radiation is an electron beam. As such,the eBeam resist composition may comprise the anti-scattering agent asthe sole resist material, the predominant resist material (i.e. greaterthan 50 wt % of the overall eBeam resist composition excluding anydiluents).

Suitably the eBeam resist composition (e.g. pre-coating) comprises adiluent or solvent. Suitably the eBeam resist composition comprisesbetween 20 and 99 wt % solvent, suitably between 50 and 97 wt %, moresuitably between 80 and 95 wt % solvent. As such, the eBeam resistcomposition suitably comprises between 1 and 80 wt % non-solventcomponents, suitably between 3 and 50 wt % non-solvent components, moresuitably between 5 and 20 wt % non-solvent components. Suitably theeBeam resist composition is a solution, suitably which is free of anydispersed or suspended particulate matter. Suitably the eBeam resistcomposition is suitable for spinning onto a surface, suitably to providea (substantially) homogeneous coating on said surface. Suitably theeBeam resist composition is (substantially) free of any particulatematter. Suitably the eBeam resist composition is (substantially) free ofany nanoparticles, especially free of any metal(0) nanoparticles ormetal-containing nanoparticles.

The eBeam resist composition may comprise a secondary electrongenerator. Such a secondary electron generator is described hereinbelow,and also in co-pending application PCT/GB2015/050884 (filed on 24 Mar.2015 by the same Applicants as the present application), which is herebyincorporated by reference. Suitably any such secondary electrongenerator is bonded (whether datively, covalently, or ionically) to theantiscattering compound/complex or to a part thereof.

The eBeam resist composition may comprise a scattering compound, whichis capable of scattering secondary electrons following irradiation withan incident eBeam but which does not (to any significant extent) amplifysecondary electrons. Suitably any such scattering compound is bonded(whether datively, covalently, or ionically) to the antiscatteringcompound/complex or to a part thereof.

In an embodiment, the eBeam resist composition comprises both asecondary electron generator and a scattering compound, and suitablyboth are bonded to the antiscattering compound or to a part thereof.

The eBeam resist composition may comprise one or more optionaladditional components.

In a particular embodiment, the eBeam resist composition comprises:

100 pbw anti-scattering compound; and

0-10000 pbw base polymeric component.

(This can also be expressed as a weight ratio of 100:0-10000 of therespective compounds, or otherwise 100:0 to 1:100 and all intermediatecompositions).

The eBeam resist composition may be a negative tone eBeam resistcomposition or a positive tone eBeam resist composition. Where an eBeamresist composition comprises a resist polymer, a negative eBeam resistcomposition will generally further comprise a negative resist agent,such as a cross-linking agent, suitably to facilitate effective curingof radiation-exposed part(s) of the negative eBeam resist composition,or a coating thereof (e.g. suitably to render the radiation-exposedpart(s) (substantially) insoluble in a developing medium, i.e.developer-insoluble). Where an eBeam resist composition comprises aresist polymer, a positive eBeam resist composition, on the other hand,may suitably lack a negative resist agent, suitably so thatradiation-exposed portions of the positive eBeam resist composition, ora coating thereof, are (substantially) soluble in a developing medium(i.e. developer-soluble). However, since the anti-scattering compoundmay itself serve as a resist material (optionally in place of some orall of any resist polymer(s)), the eBeam resist composition may be anegative tone eBeam resist composition. The above references to negativeor positive tone resist suitable specifically relate to their behaviourin electron beam lithography.

In a particular embodiment, the eBeam resist composition is a negativeeBeam resist composition, which may comprise a cross-linking agent(especially where a resist polymer is additionally present) or may befree of cross-linking agent (especially where there is little orsubstantially no resist polymer present). Suitably radiation-exposedpart(s) of the negative eBeam resist composition, or a coating thereof,become relatively insoluble in a developing medium (i.e.developer-insoluble), as compared to radiation-unexposed part(s) thereof(i.e. which are developer-soluble).

In a particular embodiment, the eBeam resist composition is a positiveeBeam resist composition, suitably which is (substantially) free of across-linking agent (especially where a sufficient amount of resistpolymer is present), suitably (substantially) free of any cross-linkingagent(s) defined in relation to a negative eBeam resist composition.Suitably radiation-exposed part(s) of the positive eBeam resistcomposition, or a coating thereof, become relatively soluble (i.e.developer-soluble) in a developing medium, as compared toradiation-unexposed part(s) thereof (i.e. which aredeveloper-insoluble). In a particular embodiment, the resist compositionis a positive resist composition where the composition comprises greaterthan or equal to 70 wt % of a positive tone resist polymer.

Anti-Scattering Compound

The anti-scattering compound suitably controls the flow and/orscattering of electrons, especially secondary electrons (but alsosuitably primary electrons, especially where eBeam radiation is used),when an eBeam resist composition or coating thereof is exposed toradiation. Such control can advantageously limit deleterious effectscaused by uncontrolled flow and/or scattering of electrons. Suitablyscattering of primary electrons is almost zero for incident electronbeams of 2 KeV and above.

Though not wishing to be bound by theory, it is thought that theanti-scattering compound of the invention may serve to channel orotherwise guide electrons to maximize the transformative impact (i.e.transformation of the resist component and optionally other relevantingredients, e.g. cross-linker) at irradiated part(s) of an eBeam resistcomposition (or a coating thereof) and minimize the transformativeimpact at neighbouring non-irradiated part(s)—i.e. making exposure moreselective. This serves to increase the resolution and consistency of thepatterning process. The anti-scattering compound may also dampen orquench (partially or completely) primary and/or secondary electrons soas to inhibit over-reaction or deleterious damage to the resist or theunderlying substrate.

Suitably, one or more components (especially complex(es), for example,polymetallic cages and/or polymetallic ring systems) of theanti-scattering compound has a molecular structure with a significantamount of free internal space. Suitably the anti-scattering compound asa whole (in view of the arrangement of the individual componentsthereof—e.g. an association of a plurality of metal cages or ringsoptionally arranged around a common hub or one or more linkercomponents) has a structure with a significant amount of internal freeinternal space. Without wishing to be bound by theory, it is thoughtthat such free empty space is a key contributor to the advantageousproperties of the anti-scattering compound, and helps to minimiseprimary electron scattering and/or secondary electron generation. Assuch, the anti-scattering compound suitably has a high mean free path(λ)—i.e. the distance between successive electron collisions is high.Suitably the anti-scattering compound has a low scattering cross-section(σ)—i.e. the chances of a collision are low.

Though metal organic frameworks (MOFs), well known in the art for theirporous open (suitably 3-dimensional) crystal structures, can providecompounds and complexes with a significant amount of free empty space(typically used in practice for the absorption of gases), theanti-scattering compound, especially when a part of an eBeam resistcoating (i.e. pre-exposed), is most suitably (substantially)non-crystalline and/or does not form 3-dimensional crystal/latticestructures. Such a lack of propensity to form 3-dimensional crystallinestructures may indicate that the anti-scattering compound has moresuitable solubility properties thereby enabling more uniform coating(e.g. spin-coating) of the eBeam resist composition. As such, mostsuitably the anti-scattering compound is not a metal-organic framework(MOF). Suitably, the anti-scattering compound is (substantially)non-porous.

The anti-scattering compound is suitably self-sacrificial, therebyselectively absorbing the impact of electrons. In this manner, theanti-scattering compound may sacrificially absorb the impact, optionallyinstead of another resist component (e.g. polymeric component). Theanti-scattering compound may itself serve as a resist component(optionally the sole resist component), for example, whosedeveloper-solubility properties change following exposure to radiation(especially eBeam radiation).

Suitably, the anti-scattering compound has a density less than or equalto 1.5 g/cm³, suitably less than 1.3 g/cm³, suitably less than or equalto 1.2 g/cm³, suitably less than or equal to 0.95 g/cm³, suitably lessthan or equal to 0.9 g/cm³, suitably less than or equal to 0.85 g/cm³,suitably less than or equal to 0.8 g/cm³, suitably less than or equal to0.7 g/cm³. Suitably the anti-scattering compound has a density greaterthan or equal to 0.4 g/cm³, suitably greater than or equal to 0.5 g/cm³,suitably greater than or equal to 0.55 g/cm³, suitably greater than orequal to 0.6 g/cm³. In a particular embodiment, the anti-scatteringcompound has a density between 0.6 g/cm³ and 0.85 g/cm³. In a particularembodiment, the anti-scattering compound has a density less than orequal to 1.2 g/cm³.

Suitably, the anti-scattering compound has a molecular weight greaterthan or equal to 2000 g/mol, suitably greater than or equal to 5000g/mol, suitably greater than or equal to 10,000 g/mol, suitably greaterthan or equal to 15,000 g/mol. Suitably, the anti-scattering compoundhas a molecular weight less than or equal to 300,000 g/mol, suitablyless than or equal to 200,000 g/mol, suitably less than or equal to100,000 g/mol, suitably less than or equal to 50,000 g/mol, suitablyless than or equal to 20,000 g/mol.

Suitably, the anti-scattering compound (substantially) does not generatesecondary electrons, as ionization products, in response to exposure toprimary radiation. The primary radiation is suitably an electron beam orelectromagnetic radiation.

The anti-scattering compound is suitably a metal-organic complex.Suitably the anti-scattering compound is a polymetallic compound. Theanti-scattering compound suitably does not comprise an elemental metal(i.e. metal(0)). Suitably any metal species of the anti-scatteringcompound are metal ions.

The anti-scattering compound suitably comprises a primary metal complex(PMC). Suitably the primary metal complex is defined as set forthherein, and is suitably a metal cage, most suitably a polymetallic cage(suitably with at least one trivalent metal species and at least onedivalent metal species, though in certain embodiments all metal speciesmay be trivalent, whether all trivalent metal species are derived fromthe same or a different metal element). Metal cages may include thosedisclosed in or similar to those disclosed in G. F. S. Whitehead, F.Moro, G. A. Timco, W. Wernsdorfer, S. J. Teat and R. E. P. Winpenny, “ARing of Rings and Other Multicomponent Assemblies of Clusters”, Angew.Chem. Int. Ed., 2013, 52, 9932-9935. In some embodiments, thepolymetallic cage is homometallic. In preferred embodiments, thepolymetallic cage is heterometallic (i.e. having two or more, mostsuitably exactly two, different metal elements).

The primary metal complex may be neutral or charged (whether positivelyor negatively). The anti-scattering compound may, especially where theprimary metal complex is charged, comprise one or more counterions (e.g.C¹, C², . . . , C^(c)), suitably as defined herein, suitably associatedwith the primary metal complex as part of a primary metal complex salt.As such, the anti-scattering compound may be defined by, or may compriseunits defined by, a primary metal complex salt of Formula A:

(C ¹ _(i1) ,C ² _(i2) . . . C ^(c) _(ic))(PMC)_(p)

wherein PMC is a primary metal complex, suitably as defined herein, andp is the relative stoichiometry of PMC in Formula A or p is the numberof moles of PMC per mole of Formula A; andwherein C¹ is a first counterion, C² is a second counterion, and C^(c)is a cth counterion, suitably as defined herein, wherein i1, i2, and ic,is the relative respective stoichiometry of each of C¹, C², . . . , andC^(c) in Formula A or i1, i2, and ic, are the respective number of molesof each of C¹, C², . . . , and C^(c) per mole of Formula A.

p may have any suitable value, and is preferably a non-zero integer. pmay suitably be a value (suitably an integer) between 1 and 6.

In preferred embodiments, there are either no counterion species (i.e.i1, i2, and ic, are all zero) associated with the primary metal complexor the primary metal complex is associated with (i.e. the primary metalcomplex salt comprises) only a single (type of) counterion species (i.e.ii is non-zero but i2, and ic are zero). Suitably the stoichiometry orrelative number of moles of PMC and counterion(s) is such that theresulting primary metal complex salt is neutral. However, the presenceof additional charged components (e.g. linker components—see below)within the anti-scattering compound may mean the primary metal complexsalt need not be neutral.

The anti-scattering compound suitably comprises a linker component (orone or more linker components), suitably associated with (e.g.electrostatically and/or covalently, most suitably at least partiallycovalently) one or more, preferably two or more primary metal complexes.Suitably the linker component(s) is defined as set forth herein, and issuitably a complex or compound capable of co-ordinating with (i.e.forming dative bonds with) one or more (preferably two or more) primarymetal complexes. The complex resulting from one or more linkercomponent(s) being associated with one or more primary metal complex(es)may be termed a “hybrid complex”.

The anti-scattering compound may be defined by, or may comprise unitsdefined by, a hybrid complex of Formula B:

(PMC)_(p)(LINK)_(l)

wherein PMC is a primary metal complex, suitably as defined herein, andp is the relative stoichiometry of PMC in Formula B or p is the numberof moles of PMC per mole of Formula B; andwherein LINK is a linker component, suitably as defined herein, and l isthe relative stoichiometry of LINK in Formula B or l is the number ofmoles of LINK per mole of Formula B.

p may have any suitable value, and is preferably a non-zero integer. pmay suitably be a value (suitably an integer) between 1 and 120 (where120 is the theoretical limit), suitably between 1 and 48. p may suitablybe a value (suitably an integer) between 1 and 30, suitably between 2and 24, more suitably between 2 and 8, suitably between 4 and 6. Mostsuitably p is an even integer (especially 2, 4, or 6).

l may have any suitable value (including 0), and is suitably zero or anon-zero integer, most suitably a non-zero integer. l may suitably be avalue (suitably an integer) between 0 and 10, suitably between 0 and 2,more suitably 0 or 1, most suitably 1.

The primary metal complex (e.g. PMC) and/or the linker component (e.g.LINK) may be neutral or charged (whether positively or negatively).Where both are present, both the primary metal complex and the linkercomponent may be charged and, in some embodiments, each may have chargesof opposing polarity (i.e. one being negatively charged, the other beingpositively charged, and potentially thereby electrostatically associatedwith one another in addition to any dative/covalent interactionstherebetween). If the primary metal complex(es) have charges of opposingpolarities to the linker component(s), the overall charges of thesespecies within the anti-scattering compound may be zero (i.e. thecharges may neutralise one another to give a compound or unit of FormulaA having no net charge). Alternatively, the anti-scattering compoundmay, especially where a hybrid complex has a net charge (i.e. isnon-neutral), comprise one or more counterions (e.g. C¹, C², . . . ,C^(c)), suitably as defined herein, suitably associated with the hybridcomplex (and/or associated with either or both of the primary metalcomplex or/and linker component) as part of a hybrid complex salt. Assuch, the anti-scattering compound may be defined by, or may compriseunits defined by, a hybrid complex salt of Formula C:

(C ¹ _(i1) C ² _(i2) . . . C ^(c) _(ic))(PMC)_(p)(LINK)_(l)

wherein PMC is a primary metal complex, suitably as defined herein, andp is the relative stoichiometry of PMC in Formula C or p is the numberof moles of PMC per mole of Formula C;wherein LINK is a linker component, suitably as defined herein, and l isthe relative stoichiometry of LINK in Formula C or l is the number ofmoles of LINK per mole of Formula C; andwherein C¹ is a first counterion, C² is a second counterion, and C^(c)is a cth counterion, suitably as defined herein, wherein i1, i2, and ic,is the relative respective stoichiometry of each of C¹, C², . . . , andC^(c) in Formula C or i1, i2, and ic, are the respective number of molesof each of C¹, C², . . . , and C^(c) per mole of Formula C.

p may have any suitable value, and is preferably a non-zero integer. pmay suitably be a value (suitably an integer) between 1 and 120 (where120 is the theoretical limit), suitably between 1 and 48. p may suitablybe a value (suitably an integer) between 1 and 30, suitably between 2and 24, more suitably between 2 and 8, suitably between 4 and 6. Mostsuitably p is an even integer (especially 2, 4, or 6).

l may have any suitable value (including 0), and is suitably zero or anon-zero integer, most suitably a non-zero integer. l may suitably be avalue (suitably an integer) between 0 and 10, suitably between 0 and 2,more suitably 0 or 1, most suitably 1.

Either or both of the primary metal complex and linker component withina hybrid complex (or salt thereof) may be each independently associatedwith any of the counterions, and/or the counterions may be associatedwith the hybrid complex as a whole.

Suitably the hybrid complex salt is neutral overall.

The anti-scattering agent may comprise one or more additional metalcomplexes (AMC) (or salt(s) thereof), optionally associated with one ormore counterions and/or one or more linker components as defined hereinin relation to the primary metal complex. Any additional metalcomplex(es) are different from the primary metal complex (e.g. be it interms of the metal species and/or ligands or the relativestoichiometries thereof). However, though different from the primarymetal complex, any, some, or all of the additional metal complex(es) maybe defined as set forth herein in relation to any primary metal complex.As such, any additional metal complex(es) may be a metal cage, such as apolymetallic cage, suitably wherein all metal species are divalent orwhere the metal sites are in different oxidation states. Thispolymetallic cage may be homometallic. However, the metal cage of theAMC may be as per any of those defined herein in relation to a primarymetal complex. Where one or more additional metal complex(es) arepresent in addition to a primary metal complex, suitably at least one,preferably two, metal species of the addition metal complex(es) aredifferent to those of the primary metal complex.

The anti-scattering agent may therefore be defined by, or may compriseunits defined by, a hybrid complex or hybrid complex salt of Formula D:

(C ¹ _(i1) C ² _(i2) . . . C ^(c) _(ic))(PMC)_(p-a)(AMC)_(a)(LINK)_(l)

wherein PMC is a primary metal complex, suitably as defined herein, andp-a is the relative stoichiometry of PMC in Formula D or p-a is thenumber of moles of PMC per mole of Formula D;wherein AMC is one or more additional metal complex(es), suitably asdefined herein (optionally in the same manner as PMC so long as theAMC(s) differ from PMC), and a is the relative stoichiometry of AMC inFormula D or a is the number of moles of AMC per mole of Formula D;wherein LINK is a linker component, suitably as defined herein, and l isthe relative stoichiometry of LINK in Formula C or l is the number ofmoles of LINK per mole of Formula C; andwherein C¹ is a first counterion, C² is a second counterion, and C^(c)is a cth counterion, suitably as defined herein, wherein i1, i2, and ic,is the relative respective stoichiometry of each of C¹, C², . . . , andC^(c) in Formula C or i1, i2, and ic, are the respective number of molesof each of C¹, C², . . . , and C^(c) per mole of Formula C.

p may have any suitable value, and is preferably a non-zero integer. pmay suitably be a value (suitably an integer) between 1 and 120 (where120 is the theoretical limit), suitably between 1 and 48. p may suitablybe a value (suitably an integer) between 1 and 30, suitably between 2and 24, more suitably between 2 and 8, suitably between 4 and 6. Mostsuitably p is an even integer (especially 2, 4, or 6).

a may have any suitable value, and is preferably zero or a non-zerointeger, a may suitably be a value (suitably an integer) between 1 and30, suitably between 2 and 24, more suitably between 2 and 8, suitablybetween 4 and 6. Most suitably a is an even integer (especially 2, 4, or6). However, suitably p-a is greater than zero.

l may have any suitable value (including 0), and is suitably zero or anon-zero integer, most suitably a non-zero integer. l may suitably be avalue (suitably an integer) between 0 and 10, suitably between 0 and 2,more suitably 0 or 1, most suitably 1.

Optionally the hybrid complex of Formula D may be free ofcounterions—i.e. all of i1, i2, . . . , ic are zero.

Suitably the antiscattering agent comprises a primary metal complex butis (substantially) free of any additional metal complex(es). However,where additional metal complex(es) are present, they may be considered asubstitute for a portion of the primary metal complex, and parametersand values may optionally be as defined herein as if the additionalmetal complex(es) were in fact the substituted primary metal complex.

References to any metal salts and/or complexes of the anti-scatteringcompound generally relate to the pre-mixed (i.e. prior to mixing withother components of the eBeam resist composition) form of suchsalts/complexes (i.e. in terms of cationic-anionic associations), andsuitably also relate to the pre-coated, pre-cured, pre-exposed,pre-baked, pre-developed form thereof. It will be appreciated by thoseskilled in the art that, upon mixing with other components of the eBeamresist composition (and/or after coating, curing, exposing, bakingand/or developing), the relevant cations, anions, and ligands of themetal salts and/or complexes of the anti-scattering compound may, insome embodiments (though not all), dissociate and possibly becomeassociated with other counterions and/or ligands. Therefore, referencesto an eBeam resist composition (or indeed a coating, or a cured-,exposed-, or developed-product thereof) suitably indicates an eBeamresist composition (or a coating, or a cured-, exposed-, ordeveloped-product thereof) “formed by” (or derived from) mixing saidanti-scattering compound with any other ingredients of the eBeam resistcomposition. It is straightforward for those skilled in the art, usingstandard techniques, to determine the input in respect of theanti-scattering compound from an eBeam resist composition or a coated,cured-, exposed-, baked- or developed-product thereof.

Suitably, any metal salts and/or complexes of the anti-scatteringcompound comprise a two or more metal species.

The anti-scattering compound is suitably soluble in any diluent(s) orsolvent(s) or diluent/solvent system of the eBeam resist composition(i.e. is soluble in a coating solvent system, which may be consideredthe diluents/solvents within the pre-coated eBeam resist composition).Suitably, at standard ambient temperature and pressure (SATP) theanti-scattering compound has a solubility of at least 1 mg/g in thecoating solvent system, suitably at least 2 mg/g, suitably at least 10mg/g, suitably at least 20 mg/g. Suitably the coating solvent system inquestion to which these solubility limits apply comprises or consistsessentially of a (1-10C)hydrocarbyl solvent system, most preferablyhexane.

The anti-scattering compound is suitably soluble in any diluent(s) orsolvent(s) or diluent/solvent system of the pre-determined developingmedium (especially where the eBeam resist composition is a negative toneeBeam resist composition). Suitably, at standard ambient temperature andpressure (SATP) the anti-scattering compound has a solubility of atleast 1 mg/g in the developing medium, suitably at least 2 mg/g,suitably at least 10 mg/g, suitably at least 20 mg/g. Suitably thedeveloping medium in question to which these solubility limits applycomprises or consists essentially of a (1-10C)hydrocarbyl solventsystem, most preferably hexane.

Most suitably, the antiscattering agent is soluble, suitably within atleast the limits defined herein, both a coating solvent system and apre-determined developing medium.

Primary Metal Complex (and/or Additional Metal Complex)

The anti-scattering compound suitably comprises a primary metal complex.Suitably the primary metal complex is a metal cage, suitably a metalcage with no metal-metal bonds.

The primary metal complex is suitably a polymetallic complex. Thepolymetallic complex may be homometallic (e.g. composed of metal speciesderived from the same element, whether or not they are of the sameoxidation state, though most suitably all the metal species of ahomometallic PMC are of the same oxidation state, suitably metal (III)).Alternatively, and most suitably, the polymetallic complex isheterometallic (e.g. composed of metal species derived from differentmetal elements, whether or not are of the same oxidation state, thoughmost suitably the relevant metal species of a heterometallic PMC are ofdifferent oxidation states, most suitably metal (II) and metal(III).

The primary metal complex suitably comprises one or more metal species,each of which may be suitably denoted M¹, M2, . . . , M^(n) (see below).As such, the primary metal compound suitably comprises at least onemetal species M¹. Suitably, where there is only one metal species M¹within a PMC, said metal species has an oxidation state of III (i.e. +3)(though for an AMC preferably II—+2). In a particular embodiment, theprimary metal complex comprises Cr(III) as the only metal species, witheach complex most suitably comprising 8 Cr(III) units each.

Suitably the primary metal complex comprises two or more(different/different types of) metal species, each of which may besuitably denoted M¹, M², . . . , M^(n). As such, suitably the primarymetal complex comprises a metal species M¹, a metal species M², andoptionally one or more additional metal species (e.g. M3, . . . ,M^(n)). Suitably the two or more (different) metal species (suitably atleast M¹ and M²) of the primary metal complex are two or more(different) metal ions. M¹ and M² are suitably derived from the samemetal element and have a different valency, or are suitably derived froma different metal element and have the same or a different valency.Suitably two or more of the (different) metal ions (suitably at least M¹and M²) have a different oxidation state, suitably an oxidation statewhich differs by one, most suitably one of the metal ions (suitably M¹)being trivalent (i.e. an oxidation state of III, or +3) and another ofthe metal ions (suitably M²) being divalent (i.e. an oxidation state ofII, or +2). Where there are two or more metal species, both or all maybe derived of the same metal element but be of a different oxidationstate. This may, for instance, include a PMC having both Fe(II) andFe(III) species.

Suitably the two or more (different) metal species (suitably at least M¹and M²) are derived from two or more different metals. As such, suitablythe anti-scattering compound is a heterometallic polymetallic compound(i.e. containing two or more different metal species). Suitably at leastone of the two or more (different) metal species (or at least one of M¹and M²) is a transition metal (d-block) species, more suitably at leasttwo of the two or more (different) metal species (or both of M¹ and M²)are transition metal (d-block) species. In an embodiment, both M¹ and M²are transition metal ions such that the primary metal complex is atransition metal complex. Suitably at least one of the two or more(different) metal species (or at least one of M¹ and M²) is a transitionmetal species of the 3d-block of the periodic table of elements, moresuitably at least two of the two or more (different) metal species (orboth of M¹ and M²) are transition metal species of the 3d-block of theperiodic table of element.

Suitably at least one of the two or more (different) metal species (orat least one of M¹ and M², most suitably M¹) is a trivalent metalspecies, suitably selected from the group including Cr^(III), Fe^(III),V^(III), Ga^(III), Al^(III), or In^(III), though most suitably thetrivalent metal species (suitably M¹) is Cr^(III). Suitably at least one(preferably one other than the aforementioned trivalent metal species)of the two or more (different) metal species (or at least one of M¹ andM², most suitably M²) is a divalent metal species, suitably selectedfrom the group including Ni^(II), Co^(II), Zn^(II), Cd^(II), Mn^(II),Mg^(II), Ca^(II), Sr^(II), Ba^(II), Cu^(II), or Fe^(II), though mostsuitably the divalent metal species (suitably M²) is Ni^(II).

In a particular embodiment, the primary metal complex (and hence theanti-scattering compound) comprises at least one trivalent metal species(suitably M¹, suitably selected from the group including Cr^(III),Fe^(III), V^(III), Ga^(III), Al, or In^(III); most suitably Cr^(III))and at least one divalent metal species (suitably M², suitably selectedfrom the group including Ni^(II), Co^(II), Zn^(II), Cd^(II), Mn^(II),Mg^(II), Ca^(II), Sr^(II), Ba^(II), Cu^(II), or Fe^(II); most suitablyNi^(II)).

Suitably the primary metal complex comprises two or more moles of themetal species (i.e. combined) per mole of primary metal complex (e.g.two or more moles of M¹ and/or M², suitably two or more moles of M¹ andM² combined—e.g. [M¹ _(x)M² _(y)] where x+y≧2), suitably three or moremoles of the metal species per mole of primary metal complex, suitablyfour or more, suitably five or more, suitably six or more, suitablyseven or more, most suitably about eight moles of the metal species permole of primary metal complex. Suitably the primary metal complexcomprises twelve or fewer moles of the metal species (i.e. combined) permole of primary metal complex, suitably ten or fewer.

Suitably, at least one of the metal species of the primary metalcomplex(es) is magnetic, suitably paramagnetic, suitably two or moremetal species thereof.

Suitably the primary metal complex comprises more (suitably by moles orstoichiometry ratio) trivalent metal species (e.g. M¹) than divalentmetal species (e.g. M²), suitably at least two times more, suitably atleast three times more, suitably at least four times more, suitably atleast seven times more. Suitably the molar ratio of M¹ (which issuitably trivalent) to M² (which is suitably divalent) within theprimary metal complex is between 12:1 and 1:1, suitably between 10:1 and2:1, suitably between 9:1 and 3:1, more suitably between 8:1 and 6:1,most suitably about 7:1.

The primary metal complex suitably comprises one or more ligands,suitably one or more ligands co-ordinated to one, more, or all (or both)of the metal species (e.g. M¹ and/or M²) of the primary metal complex.The primary metal complex suitably comprises ligands (including mixturesof ligands) of a sufficient type and in sufficient numbers to bindtogether (suitably indirectly, suitably via dative bonds) all of themetal species within the primary metal complex, suitably to form a metalcage, suitably without any metal-metal bonds. As such, the primary metalcomplex suitably comprises one or more bridging ligands, suitably whichare capable of providing a bridge between two or more metal species—suchbridging ligands may be polydentate, such as bidentate, but may also bemonodentate where they are capable of donating more than one lone pairif electrons, such as with fluoro or oxygen-based ligands). Mostsuitably the primary metal complex comprises a mixture of two or moredifferent types of ligand, wherein suitably one of the types of ligandis bidentate and another is monodentate. Most suitably, all of theligands within the primary metal complex have co-ordinating atomscapable of donating more than one lone pair of electrons. Suitably, theprimary metal complex comprises ligands of sufficient types and numbers(may be a mixture of monodentate ligands such as fluoro, and bidentateligands such as carboxylate) to afford an average of at least 3 dativebonds per individual metal species within the complex (e.g. eachindividual M¹ and M² species within a complex forms an average of atleast 3 dative bonds with ligands associated with the complex), suitablyat least 4 dative bonds, most suitably about 6 dative bonds. Suitablythe co-ordination sites of all the metal species may be completelyfilled/saturated (e.g. especially where the primary metal complex isintended to serve as a lewis basis within the overall anti-scatteringcompound) by the ligands within the complex, or there may be one or morevacant co-ordination sites amongst the metal species (e.g. especiallywhere the primary metal complex is intended to serve as a lewis acidwithin the overall anti-scattering compound).

Suitably at least some, suitably all, ligands are negatively charged,most suitably bearing a single negative charge. Suitably the conjugateacid of the ligand(s) of the primary metal complex have a pK_(a) value(in water at standard ambient temperature and pressure) greater than orequal to 2, suitably greater than or equal to 3.

Suitably, the ligand(s) of the primary metal complex are selected frommonodentate ligands, bidentate ligands, or mixture(s) thereof. Mostsuitably, the ligand(s) of the primary metal complex comprise a mixtureof monodentate ligands and bidentate ligands.

The monodentate ligand(s) suitably have a co-ordinating atom(s) (theatoms to and/or from which dative bonds are formed with metal species)bearing more than one lone pair of electrons, most suitably fluoride.

The bidentate ligands suitably have at least one, more suitably two,co-ordinating atoms bearing more than one lone pair of electrons, mostsuitably carboxylate (e.g. an optionally substituted organiccarboxylate, e.g. optionally substituted hydrocarbyl carboxylates, suchas acetate, pivalate, 3,3-dimethylbutanoate, benzoate,4-tert-butylbenzoate, isonicotinate). In some embodiments (especiallywhere the primary metal complex is intended to serve as a Lewis base),the ligands of the primary metal complex comprise at least two differenttypes of bidentate ligand (e.g. comprise a first and second bidentateligand) or carboxylate ligand. In such embodiments, suitably at leastone of the bidentate ligands (e.g. the second) comprises a co-ordinatingatom(s) capable of forming an internal dative bond(s) with metal specieswithin the primary metal complex and one or more additionalco-ordinating atoms capable of forming external dative bonds with metalspecies of another (different) complex or cage. Suitably suchbifunctional ligands (e.g. the second bidentate ligand) may include acarboxylate group and an additional oxygen- or nitrogen-containingmoiety, preferably a nitrogen-containing moiety, examples of whichinclude iso-nicotinate and 4-aminobenzoate. However, in some embodiments(especially where the primary metal complex is intended to serve as aLewis acid), the ligands of the primary metal complex are free of anyadditional co-ordinating atoms capable of forming external dative bondswith metal species of another (different) complex or cage, and maysuitably comprise one type of bidentate ligand or carboxylate ligand.

In a particular embodiment, the primary metal complex is defined byFormula I or comprises units defined by Formula I:

[M ¹ _(x) M ² _(y . . .) M ^(n)_(zn)(monoLIG¹)_(m1)(monoLIG²)_(m2 . . .)(monoLIG^(q))_(mq)(biLIG¹)_(b1)(biLIG²)_(b2 . . .)(biLIG^(r))_(br)(optLIG^(s))(optLIG¹)_(o1)(optLIG²)_(o2 . . .)(optLIG^(s))_(os)];

-   -   OR        is defined as comprising, consisting essentially of, or being        formed by mixing together, reacting, or otherwise combining (per        each mole of primary metal complex):

x moles of a first metal species (M¹)

y moles of a second metal species (M²);

optionally zn moles of each additional nth metal species (M^(n));

m1 moles of a first monodentate ligand (monoLIG¹)

optionally m2 moles of a second monodentate ligand (monoLIG²)

optionally mq moles of each additional qth monodentate ligand(monoLIG^(q))

b1 moles of a first bidentate ligand (biLIG¹)

optionally b2 moles of a second bidentate ligand (biLIG²)

optionally br moles of each additional rth bidentate ligand (biLIG^(r))

o1 moles of a first optional extra/terminal ligand (optLIG¹)

o2 moles of a second optional extra/terminal ligand (optLIG²)

os moles of each additional optional sth extra/terminal ligand(optLIG^(s))

wherein:

-   -   M¹ is a first metal species, suitably as defined herein (most        suitably a trivalent metal ion, e.g. Cr³⁺);    -   M² is a second metal species, suitably as defined herein (most        suitably a divalent metal ion, e.g. Ni²⁺);    -   M^(n) is an nth metal species, suitably as defined herein (most        suitably is absent);    -   monoLIG¹ is a first monodentate ligand, suitably as defined        herein (most suitably a monoanion whose conjugate acid has a        pK_(a ≧)2, suitably fluoride);    -   monoLIG² is a second monodentate ligand, suitably as defined        herein (most suitably absent);    -   monoLIG^(q) is a qth monodentate ligand, suitably as defined        herein (most suitably absent);    -   biLIG¹ is a first bidentate ligand, suitably as defined herein        (most suitably carboxyate, suitably without any additional        heteroatoms);    -   biLIG² is a second bidentate ligand, suitably as defined herein        (most suitably absent or a carboxylate bearing an additional        oxygen- or nitrogen-containing moiety, most preferably an        additional nitrogen-containing moiety);    -   biLIG^(r) is a rth bidentate ligand, suitably as defined herein        (most suitably absent);    -   optLIG¹ is a first optional extra ligand (suitably having a        denticity of d), suitably as defined herein (most suitably        absent, or is a polydentate ligand of denticity d, such as        N-methyl-D-glucamine where d=6, a solvent or carboxylic acid);    -   optLIG² is a second optional extra/terminal ligand, suitably as        defined herein (most suitably absent or a solvent or carboxylic        acid);    -   optLIG^(s) is a sth optional extra/terminal ligand, suitably as        defined herein (most suitably absent or a solvent or carboxylic        acid);

Most suitably x, y, zn, m1, m2, mq, b1, b2, br, o1, o2, os, are zero orintegers, though in some examples any, some, or all of these may have anintermediate value between 0 and 1 or between any two integers.

x is suitably a number (most suitably an integer) between 1 and 16,suitably between 4 and 10; more suitably between 2 and 8; suitably 7.

y is suitably a number (most suitably an integer) between 0 and 15,suitably between 0 and 7; suitably between 0 and 2, suitably 0 or 1,most suitably 1.

zn is suitably a number (most suitably an integer) between 0 and 14,suitably between 0 and 6; suitably between 0 and 2; suitably 0.

m1 is suitably a number (most suitably an integer) between 0 and 40;suitably between 0 and 20 or between 0 and 10; suitably between 1 and20; suitably between 2 and 12; suitably between 4 and 10; suitably 8.

m2 is suitably a number (most suitably an integer) between 0 and 39;suitably between 0 and 18; suitably between 0 and 10; suitably between 0and 2; suitably 0.

mq is suitably a number (most suitably an integer) between 0 and 38;suitably between 0 and 17; suitably between 0 and 9; suitably between 0and 2; suitably 0.

b1 is suitably a number (most suitably an integer) between 0 and 20;suitably between 1 and 20; suitably between 1 and 16; suitably between12 and 16; suitably between 12 and 15; suitably 15 or 16.

b2 is suitably a number (most suitably an integer) between 0 and 20;suitably between 0 and 16; suitably between 0 and 8; suitably between 0and 3; suitably between 1 and 4; suitably 0 or 1.

br is suitably a number (most suitably an integer) between 0 and 19;suitably between 0 and 15; suitably between 0 and 7; suitably between 0and 2; suitably 0.

o1 is suitably a number (most suitably an integer) between 0 and 8,suitably between 0 and 4, suitably 0 or 1, most suitably 0.

o2 is suitably a number (most suitably an integer) between 0 and 7,suitably between 0 and 3, suitably 0 or 1, most suitably 0.

os is suitably a number (most suitably an integer) between 0 and 6,suitably between 0 and 2, suitably 0 or 1, most suitably 0.

In an embodiment, the primary metal complex is defined by Formula I orcomprises units defined by Formula I:

[M ¹ _(x) M ² _(y . . .) M ^(n)_(zn)(monoLIG¹)_(m1)(monoLIG²)_(m2 . . .)(monoLIG^(q))_(mq)(biLIG¹)_(b1)(biLIG²)_(b2 . . .)(biLIG^(r))_(br)(optLIG^(s))(optLIG¹)_(o1)(optLIG²)_(o2 . . .)(optLIG^(s))_(os)];

wherein:

-   -   M¹ is a first metal species and x is the number of moles of M¹        per mole of primary metal complex, wherein x is a number between        1 and 16;    -   M² is a second metal species and y is the number of moles of M²        per mole of primary metal complex, wherein y is a number between        0 and 7;    -   M^(n) is an nth metal species and zn is the number of moles of        each M^(n) per mole of primary metal complex, wherein zn is a        number between 0 and 6; suitably between 0 and 2; suitably 0;    -   monoLIG¹ is a first monodentate ligand and m1 is the number of        moles of monoLIG¹ per mole of primary metal complex, wherein m1        is a number between 0 and 20;    -   monoLIG² is a second monodentate ligand and m2 is the number of        moles of monoLIG² per mole of primary metal complex, wherein m2        is a number between 0 and 10;    -   monoLIG^(q) is a qth monodentate ligand and mq is the number of        moles of each monoLIG^(q) per mole of primary metal complex,        wherein mq is a number between 0 and 2;    -   biLIG¹ is a first bidentate ligand and b1 is the number of moles        of biLIG¹ per mole of primary metal complex, wherein b1 is a        number between 1 and 20;    -   biLIG² is a second bidentate ligand and b2 is the number of        moles of biLIG² per mole of primary metal complex, wherein b2 is        a number between 0 and 16;    -   biLIG^(r) is a rth bidentate ligand and br is the number of        moles of each additional biLIG^(r) per mole of primary metal        complex, wherein br is a number between 0 and 2;    -   optLIG¹ is a first optional extra ligand and o1 is the number of        moles of optLIG¹ per mole of primary metal complex, wherein o1        is a number between 0 and 4;    -   optLIG² is a second optional extra/terminal ligand and o2 is the        number of moles of optLIG² per mole of primary metal complex,        wherein o2 is a number between 0 and 3;    -   optLIG^(s) is a sth optional extra/terminal ligand and os is the        number of moles of each additional optional optLIG^(s) per mole        of primary metal complex; wherein os is a number between 0 and        2.

In an embodiment, the primary metal complex is defined by Formula Ia orcomprises units defined by Formula I:

[M ¹ _(x) M ² _(y)(monoLIG¹)_(m1)(biLIG¹)_(b1)(biLIG²)_(b2)];

wherein:

-   -   M¹ is a first metal species and x is the number of moles of M¹        per mole of primary metal complex, wherein x is a number between        4 and 10;    -   M² is a second metal species and y is the number of moles of M²        per mole of primary metal complex, wherein y is a number between        0 and 2;    -   monoLIG¹ is a first monodentate ligand and m1 is the number of        moles of monoLIG¹ per mole of primary metal complex, wherein m1        is a number between 4 and 10;    -   biLIG¹ is a first bidentate ligand and b1 is the number of moles        of biLIG¹ per mole of primary metal complex, wherein b1 is a        number between 12 and 16;    -   biLIG² is a second bidentate ligand and b2 is the number of        moles of biLIG² per mole of primary metal complex, wherein b2 is        a number between 0 and 3.

Suitably, the sum of x and y is at least 2, more suitably at least 3,suitably at least 4, suitably at least 5, suitably at least 6, suitablyat least 7, suitably about 8. Suitably, the sum of x and y is at most16, suitably at most 12, suitably at most 10. Suitably x is at least 4,suitably at least 6, suitably at most 10, and is most suitably about 7.In a particular embodiment y is 0 (i.e. there is no second metal speciesat all), but preferably y is non-zero, suitably at least 1, and is mostsuitably about 1. Most suitably, x is 7+/−δ (i.e. δ=at most 10% of x,suitably at most 1% of x) and y is 1−/+δ. In a particular embodiment, M₁is Cr³⁺, M₂ is Ni²⁺, the sum of x and y is between 7 and 10; and x isbetween 6 and 10. In a particular embodiment, M₁ is Cr³⁺, M₂ is Ni²⁺, xis about 7 and y is about 1.

Most suitably the primary metal complex comprises no further metalspecies beyond the first metal species (M¹) and optionally the secondmetal species (M²), and thus zn is zero. However, in some examples, theprimary metal complex may be doped, for instance, with small quantitiesof alternative metal species to judiciously vary the properties of theanti-scattering compound. In such embodiments, the sum of any or all znvalues (z3+z4+ . . . +zn) is suitably less than the sum of x and y,suitably at least 5 times less (i.e. at most a fifth of the sum of x+y),suitably at least 10 times less, suitably at least 100 times less.

Suitably, the sum of:

-   -   (m1+m2+ . . . +mq); (i.e. the sum of moles of monodentate        ligand(s) per mole of complex)    -   2×(b1+b2+ . . . +bq); (i.e. twice the sum of moles of bidentate        ligand(s) per mole of complex)    -   o1×d (i.e. d times the moles of optional extra ligand(s) per        mole of complex)        is less than or equal to 50, suitably less than or equal to 42,        suitably less than or equal to 40, suitably more than or equal        to 30, suitably more than or equal to 38, suitably about 40.

Suitably, the sum of m1, m2, . . . , and mq is at least 1, suitably atleast 2, suitably at least 3, suitably at least 6, suitably at most 7,suitably at most 16, suitably at most 12, suitably at most 10, mostsuitably about 8. In preferred embodiments, there are no monodentateligands beyond a first monodentate ligand (i.e. m2 and mq are both 0).In a particular embodiment, monoLIG¹ is fluoride (F). In a particularembodiment, monoLIG¹ is fluoride (F), m1 is between 2 and 9, and all ofm2 and mq are 0, wherein suitably M₁ is Cr³⁺, M₂ is Ni²⁺, the sum of xand y is between 7 and 10; and x is between 6 and 10. In a particularembodiment, monoLIG¹ is fluoride (F), m1 is 3, and all of m2 and mq are0 (i.e. no other monodentate ligands). In a particular embodiment,monoLIG¹ is fluoride (F), m1 is 8, and all of m2 and mq are 0 (i.e. noother monodentate ligands).

Suitably, the sum of b1, b2, . . . , and br is at least 6, suitably atleast 10, suitably at least 14, suitably at most 22, suitably at most20, suitably at most 18, most suitably about 16. In some embodiments,there are no bidentate ligands beyond a first and second bidentateligand (i.e. all br are 0), and in some embodiments there are nobidentate ligands beyond a first bidentate ligand (i.e. b2 and br areboth 0). In an embodiment, biLIG¹ is a carboxylate defined by theformula —O₂CR_(B1) (or R_(B1)CO₂ ⁻), wherein R_(B1) is suitably a group(e.g. hydrocarbyl moiety) devoid of basic or chelating groups, and issuitably selected from (1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl,(3-8C)cycloalkyl, (3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, aryl(1-3C)alkyl.Most suitably R_(B1) is (1-5C)alkyl, most suitably biLIG¹ is pivalate.In an embodiment, biLIG² is a carboxylate defined by the formula—O₂CR_(B2) (or R_(B2)CO₂ ⁻), wherein R_(B2) is suitably a groupcomprising a basic or chelating group (e.g. a moiety with a lone pair ofelectrons that is free to co-ordinate to form a dative bond), and issuitably selected from optionally substituted heterocyclyl, heteroaryl,heterocyclyl(1-6C)alkyl, heteroaryl(1-6C)alkyl, or is selected from(1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl, (3-8C)cycloalkyl,(3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, oraryl(1-3C)alkyl, substituted with one or more basic or chelating groups,for example, amino, alkylamino, dialkylamino, hydroxyl, (1-6C)alkoxy,carbonyl, immino, thio, thiocarbonyl, etc. Most suitably R_(B2) ispyridyl, aminophenyl, N-(1-3C)alkylaminophenyl,N,N-di(1-3C)alkylaminophenyl, most suitably pyridyl, most suitably4-pyridyl, most suitably biLIG² is isonicotinate. In a particularembodiment, biLIG¹ is an optionally substituted hydrocarbyl carboxylate(e.g. (1-6C)alkylcarboxylate, such as pivalate), biLIG² is an organic oroptionally substituted hydrocarbyl carboxylate bearing at least oneadditional heteroatom (e.g. one capable of acting as a lewis base orligand for chelating metal species external to the complex, e.g.isonicotinate), b1 is between 12 and 20 (most suitably 14-18, mostsuitably 15-16), b2 is between 0 and 4 (most suitably 0 or 1-3), whereinsuitably M₁ is Cr³⁺, M₂ is Ni²⁺, the sum of x and y is between 7 and 10;and x is between 6 and 10, and wherein suitably monoLIG¹ is fluoride(F), m1 is between 2 and 9, and all of m2 and mq are 0.

Suitably, the sum of o1, o2, . . . , and os is between 0 and 4, suitablybetween 0 and 2, most suitably between 0 and 1. In some embodiments,there are no optional extra/terminal ligands beyond a first optionalextra/terminal ligand (i.e. all o2 and os are 0), In a particularembodiment, the sum of o1, o2, . . . , and os is zero (i.e. there aresubstantially no optional extra/terminal ligands). Where one or moreoptional extra/terminal ligands are present, these may include a solventmolecule (be it monodentate, bidentate, or otherwise polydentate), suchas H₂O, tetrahydrofuran, pyridine, etc. In certain embodiments, theprimary metal complex comprises at least one extra/terminal ligands thatis a polydentate ligand having a denticity greater than or equal to 3,suitably greater than or equal to 4, though suitably at most 6. Suchpolydentates may, for example, include N-(1-6C)alkyl-D-glucamine (e.g.N-methyl-D-glucamine). In a particular embodiment, optLIG¹ is defined bythe formula Gluc-NH—R_(O1), wherein Gluc-NH—R_(O1) isN-(1-8C)alkyl-D-glucamine or a deprotonated form thereof, and whereinsuitably R_(O1) is (1-8C)alkyl, more suitably (1-2C)alkyl (e.g. methylor ethyl). In such embodiments, suitably o1 is 1 whilst o2 and all osare zero.

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula II:

[M ¹ _(x) M ² _(y)(monoLIG¹)_(m1)(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]

wherein:

M¹ is a trivalent metal ion as defined herein, most suitably Cr³⁺;

M² is a divalent metal ion as defined herein, most suitably Ni²⁺;

x is as defined herein (suitably x is 6, 7, 8, or 9, most suitably x is7);

y is as defined herein (suitably y is 1 or 2, most suitably y is 1,though it may be 0 form homometallic polymetallic complexes have a metalof the same oxidation state, e.g. Cr(III));

monoLIG¹ is as defined herein (most suitably monoLIG¹ is fluoride, F);

m1 is as defined herein (most suitably m1 is 8);

R_(B1) is as defined herein, though R_(B1) is suitably a group devoid ofbasic or chelating groups, and is suitably selected from (1-12C)alkyl,(1-12C)alkenyl, (1-12C)alkynyl, (3-8C)cycloalkyl, (3-8C)cycloalkenyl,(1-3C)alkyl(3-8C)cycloalkyl, (1-3C)alkyl(3-8C)cycloalkenyl, aryl,(1-3C)alkylaryl, aryl(1-3C)alkyl;

R_(B2) is as defined herein, though R_(B2) is suitably a groupcomprising a basic or chelating group (e.g. a moiety with a lone pair ofelectrons that is free to co-ordinate to form a dative bond), and issuitably selected from optionally substituted heterocyclyl, heteroaryl,heterocyclyl(1-6C)alkyl, heteroaryl(1-6C)alkyl, or is selected from(1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl, (3-8C)cycloalkyl,(3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, oraryl(1-3C)alkyl, substituted with one or more basic or chelating groups,for example, amino, alkylamino, dialkylamino, hydroxyl, (1-6C)alkoxy,carbonyl, immino, thio, thiocarbonyl, etc.;

b2 is as defined herein, though b2 is suitably 0, 1, 2, or 3;

wherein suitably the sum of x and y is as defined herein, though mostsuitably the sum of x and y is 7, 8, 9, or 10 (most suitably 8).

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IIa:

[M ¹ _(8-y) M ² _(y)F₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]

wherein:

M¹ is a trivalent metal ion as defined herein, most suitably Cr³⁺;

M² is a divalent metal ion as defined herein, most suitably Ni²⁺;

y is 0 or 1;

R_(B1) is a group devoid of basic or chelating group, and is suitablyselected from (1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl,(3-8C)cycloalkyl, (3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, aryl(1-3C)alkyl;

R_(B2) is a group comprising a basic or chelating group (e.g. a moietywith a lone pair of electrons that is free to co-ordinate to form adative bond), and is suitably selected from optionally substitutedheterocyclyl, heteroaryl, heterocyclyl(1-6C)alkyl,heteroaryl(1-6C)alkyl, or is selected from (1-12C)alkyl, (1-12C)alkenyl,(1-12C)alkynyl, (3-8C)cycloalkyl, (3-8C)cycloalkenyl,(1-3C)alkyl(3-8C)cycloalkyl, (1-3C)alkyl(3-8C)cycloalkenyl, aryl,(1-3C)alkylaryl, or aryl(1-3C)alkyl, substituted with one or more basicor chelating groups, for example, amino, alkylamino, dialkylamino,hydroxyl, (1-6C)alkoxy, carbonyl, immino, thio, thiocarbonyl, etc.;

b2 is 0, 1, 2, or 3.

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IIb:

[Cr₇NiF₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)];

wherein R_(B1), R_(B2), and b2 are as defined herein, though mostsuitably R_(B1) is t-butyl and R_(B2) if present is 4-pyridyl.

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IIc:

[Cr₇NiF₈(O₂CR_(B1))₁₆];

wherein R_(B1) is as defined herein, though most suitably R_(B1) ist-butyl.

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IId:

[Cr₈F₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)];

wherein R_(B1), R_(B2), and b2 are as defined herein, though mostsuitably R_(B1) is t-butyl and R_(B2) if present is 4-pyridyl.

In a particular embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IIe:

[Cr₈F₈(O₂CR_(B1))₁₆];

wherein R_(B1) is as defined herein, though most suitably R_(B1) ist-butyl.

In another embodiment, the primary metal complex is defined by orcomprises units defined by the Formula III:

[M ¹ _(8-y) M ² _(y)F₃(O₂CR_(B1))₁₅(Gluc-NH—R_(O1))]

wherein:

M¹ is a trivalent metal ion as defined herein, most suitably Cr³⁺;

M² is a divalent metal ion as defined herein, most suitably Ni²⁺;

y is 0 or 1;

R_(B1) is a group devoid of basic or chelating group, and is suitablyselected from (1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl,(3-8C)cycloalkyl, (3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, aryl(1-3C)alkyl;

Gluc-NH—R_(O1) is N-(1-8C)alkyl-D-glucamine (i.e. R_(O1) is (1-8C)alkyl,more suitably (1-2C)alkyl) or a deprotonated form thereof.

In another embodiment, the primary metal complex is defined by orcomprises units defined by the Formula IIIa:

[Cr₇NiF₃(O₂CR_(B1))₁₅(Gluc-NH—R_(O1))]

wherein R_(B1) and Gluc-NH—R_(O1) are as defined herein, though mostsuitably R_(B1) is t-butyl and R_(O1) is methyl.

Counterions

The primary metal complex may be neutral or charged (whether positivelyor negatively), depending on the balance and type of metal species andassociated ligands within the complex. This is likewise the case for anyadditional metal complex(es) and any linker component(s). Moreover, thecombination of primary metal complex(es), any linker component(s),and/or any additional metal complex(es), in their relevantstoichiometries may yield a net charge. As such, the anti-scatteringcompound may comprise one or more counterions (e.g. C¹, C², . . . , C),suitably as defined herein. Such counterion(s) are suitably associatedwith the primary metal complex, one or more additional metalcomplex(es), a linker component, and/or a hybrid complex as a whole. Ahybrid complex may be defined by or comprise units defined by Formula E:

(PMC)_(p-a)(AMC)_(a)(LINK)_(l)

wherein PMC, AMC, LINK, p, a, and l are as defined herein, suitably withrespect to Formula D;and a corresponding hybrid complex salt, with which the aforementionedcounterions are associated, is suitably defined by or comprise unitsdefined by Formula D:

(C ¹ _(i1) C ² _(i2) . . . C ^(c) _(ic))(PMC)_(p-a)(AMC)_(a)(LINK)_(l)

wherein Formula D and the constitutent parts thereof are as definedherein.

In the event that the hybrid complex of Formula E (or indeed of FormulaB) is neutral, the anti-scattering compound may be free from counterionsas defined herein, though this need not exclude instances wherecomplexes or components of the hybrid complex act as counterions to eachother.

The counterion(s) may be any suitable counterion(s), and may be eitherpositively (countercations) or negatively (counteranions) chargeddepending on the polarity of the charge borne on species to which thecounterions are intended to neutralise.

In preferred embodiments, the net charge of the primary metal complex isnegative (i.e. producing an anionic complex), most suitably having anegative charge of about −1. Moreover, in preferred embodiments, the netcharge of the hybrid complex (whether of Formula B or E) is negative. Assuch, the anti-scattering compound suitably additionally comprises oneor more countercations, suitably a single countercation (i.e. just C¹but no C² . . . c), to neutralise the negative charge of the relevantcomplex(es).

The countercation(s) may be any suitable cation(s). However, inpreferred embodiments, the countercation(s) comprise (and preferablyconsist essentially of) a monovalent cation (i.e. +1 charged), suitablyselected from an alkali metal cation or an ammonium-based cation(including any ammonium, primary ammonium, secondary ammonium, tertiaryammonium, quaternary ammonium cation, imidazolium), most suitably acation selected from the group including NH₃R_(cat1) ⁺, NH₂R_(cat2) ⁺,Cs⁺, Rb⁺, wherein R_(cat1) and R_(cat2) are each independently selectedfrom (1-12C)alkyl (most suitably (1-4C)alkyl, especially ethyl orpropyl). Dipropylammonium salts are particularly useful.

Linker Component (or Central Complex)

The anti-scattering compound suitably comprises a linker component.Suitably the linker component indirectly links (or associates) togethertwo or more primary metal complexes and/or indirectly links (orassociates) together one or more primary metal complexes with one ormore additional metal complexes, suitably via the linker component.Suitably the linker component is capable of forming electrostatic and/orcovalent bonds with two or more primary metal complexes and/or with oneor more primary metal complexes and with one or more additional metalcomplexes.

Suitably, where a linker component is defined by reference to a radicalspecies (e.g. halo) it may instead refer to an ionic form thereof (e.g.halide).

The linker component may comprise one or more, suitably two or more,Lewis basic moieties and/or one or more Lewis acidic moieties. As such,the linker component may comprise one or more, suitably two or more,electron pair donars and/or one or more, suitably two or more, electronpair acceptors. In preferred embodiments the linker component forms abridge (or hub) between two or more primary metal complexes and/orbetween one or more primary metal complexes and one or more additionalmetal complexes, and as such the linker component suitably comprises atleast one Lewis acid or base moiety which binds (suitably via a dativebond) one complex and at least one other Lewis acid or base moiety whichbinds (suitably via a dative bond) another complex.

The anti-scattering compound or hybrid complex (or salt thereof) maycomprise one or more moles of linker component(s) (whether the same ordifferent linker components, suitably the same) per mole of compound orhybrid complex, but most suitably the anti-scattering compound or hybridcomplex (or salt thereof) comprises only one mole of linker componentper mole of compound or hybrid complex. As such, the linker componentmost suitably serves, within a hybrid complex, as a common central hubto which (or with which) primary metal complex(es) and/or additionalmetal complex(es) (though most suitably just primary metal complexes)are connected (or associated). Suitably, this common central hub issurrounded by two or more primary metal complex(es) and/or additionalmetal complex(es), more suitably by four or more primary metalcomplex(es) and/or additional metal complex(es). As such, suitably thelinker component comprises an appropriate number of lewis acid or basemoieties to enable the linker component to bond (preferably via dativebonds) to all of its surrounding primary metal complex(es) and/oradditional metal complex(es), suitably via dative bonds. However, incircumstances where the linker moiety is only associated with a singleprimary metal complex and no additional metal complexes, the linkercomponent may be simply a terminal ligand, such as those selected fromoptLIG², such as a solvent molecule (e.g. water, THF, pyridine, orsubstitute pyridine).

The anti-scattering compound suitably comprises a hybrid complex definedby or comprises units defined by Formula E:

(PMC)_(p-a)(AMC)_(a)(LINK)_(l)

wherein l is 1; p is ≧2 (suitably between 2 and 8, more suitably 2, 4,or 6, though p may be between 23 and 49); and a is between 0 and 7(suitably 0).

The linker component, or LINK group/molecule, suitably provides one ormore, preferably two or more, electron pair-donating and/orelectron-pair accepting co-ordinating groups. Though in someembodiments, the linker component may comprise a mixture of electronpair-donating and electron pair-accepting co-ordinating groups, mostpreferably the linker component comprises either exclusively electronpair-donating or electron pair-accepting co-ordinating groups. Whetherthe linker component comprises electron pair-donating or electronpair-accepting co-ordinating groups suitably depends on the electronpair-dontaining or electron-pair accepting capacity of correspondingprimary metal complexes and optional additional metal complexes (inparticular the ligands thereof).

The or each linker component, especially where two or more PMCs or twoor more PMCs/AMCs combined are associated with said linker component,may be or comprise units independently selected from:

i) a single atom, molecule, ion, or complex containing a singleco-ordinating moiety capable of accepting or donating two or more lonepairs of electrons;

ii) a single molecule, ion, or complex (e.g. a multipleheteroatom-containing optionally substituted acyclic, cyclic,polycyclic, or macrocyclic molecule; or a Lewis acidic metal-centeredcompound or complex; or a metal-centered compound or complex attached toa leaving group or substitutable ligand) comprising two or moreco-ordinating moieties (e.g. internal heteroatoms, such as nitrogen,oxygen, or sulphur, or external heteroatoms borne by optionalsubstituents; or electron-deficient metal centers; or metal centersattached to a leaving group or substitutable ligand), each co-ordinatingmoiety being capable of accepting or donating one or more lone pairs ofelectrons;

iii) a molecule, ion, or complex defined by Formula IV:

Q-[CORE]-[W] _(w)

wherein:

[CORE] is absent or is the core of the linker component and comprisesone or optionally more than one core groups;

Q is a group directly attached to [CORE] or to one or more core group(s)thereof, wherein Q comprises a co-ordinating moiety (suitably aco-ordinating moiety that co-ordinates to a primary metal complex);

each W is a group independently directly attached to [CORE] or to one ormore core group(s) thereof, and optionally further attached to one ormore other W groups or to Q, each of which W independently comprises aco-ordinating moiety (suitably a co-ordinating moiety that co-ordinatesto a primary metal complex different to that associated with Q, or anadditional metal complex);

wherein w is an integer greater than zero.

The Q and one, more, or all of the W groups may be the same ordifferent. However, even if the Q and one, more, or all of the W groupsare different, they are suitably selected from the same pool ofacceptable groups.

Where a linker component is a single atom, molecule, ion, or complexcontaining a single co-ordinating moiety capable of donating two or morelone pairs of electrons, suitably the single co-ordinating moietycomprises or consists of an oxygen, sulphur, or halo (particularlyfluoro or chloro, especially fluoro) atom. For example, the linkercomponent(s) may be or comprise a group selected from halide (preferablyfluoro), oxo, oxide, hydroxide (OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy,(2-6C)alkynyloxy, formyl, carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl,(2-6C)alkanoyloxy, sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio,(2-6C)alkenylthio, (2-6C)alkynylthio, thiocarbonyl, heterocyclylcontaining at least one internal heteroatom selected from oxygen orsulphur, or (where appropriate) a deprotonated form or salt thereof;wherein any CH, CH₂, or CH₃ is optionally substituted.

Where a linker component is a single atom, molecule, ion, or complexcontaining a single co-ordinating moiety capable of accepting two ormore lone pairs of electrons, suitably the single co-ordinating moietycomprises or consists of a Lewis acidic metal atom (which may includeboron or silicon), or a metal atom attached to a leaving group orsubstitutable ligand. For example, the linker component(s) may be orcomprise a group selected from a metal cation (e.g. a divalent metalcation), a Lewis acidic metal compound (suitably a Lewis acid metalcompound, such as AlCl₃, FeCl₃, ZnCl₂, etc.), a Lewis acidic metalcomplex (suitably a Lewis acid or a complex with one or more freeco-ordination sites, such as where the metal center has fewer than 18electrons in its valence shell), and/or a metal compound or complexcomprising a leaving group or substitutable ligand (suitably where theconjugate acid of said leaving group or substitutable ligand has a pKain water at standard ambient temperature and pressure less than or equalto 1, suitably less than or equal to 0, suitably less than or equal to−1, more suitably less than or equal to −5). Suitable metal cations mayinclude divalent (e.g. alkaline earth metal, transition metal (II), orSn²⁺ cations), trivalent (e.g. Al³⁺, transition metal(III) or f-blockmetal(III) cations), or tetravalent (Sn⁴⁺, Pb⁴⁺, transition metal(IV) orf-block metal(IV) cations) cations, most suitably divalent cations.Suitably Lewis acidic metal compounds may include boron compounds (e.g.boron halides, alkoxides, etc.), silicon compounds (e.g. silane,silioxane, silicon halides, etc.), Lewis acidic metal compounds (e.g.AlCl₃, FeCl₃, ZnCl₂, etc.). Suitable Lewis acidic metal complexes orcomplexes comprising a leaving group or substitutable ligand may includecarboxylate complexes such as dimetallic carboxylate complexes (e.g.[M₂(O₂C—R)₄], where M may be Cu²⁺, Ru²⁺, Rh²⁺), trimetallic carboxylatecomplexes (e.g. [M₂M′O(O₂CR)₆], where M may be a trivalent metal ion,and M′ may be a divalent metal ion), hexametallic carboxylate complexes(e.g. [M′₄M₂O₂(O₂CR)₁₂] where M may be a trivalent metal ion, and M′ maybe a divalent metal ion), a dodecametallic complex (e.g.[Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆] where chp=6-chloro-2-pyridonate), metalcompounds whose metal center is bonded to a leaving group (e.g. a halidesuch as chloride, e.g. AlCl₃), metal complexes whose metal centre(s) areco-ordinated with a substitutable ligand such as halide, water, asolvent such as THF, pyridine, or even carboxylate.

Where a linker component is a single molecule, ion, or complexcomprising two or more co-ordinating moieties, each being capable ofdonating one or more lone pairs of electrons, suitably each of the twoor more co-ordinating moieties comprises or consists of an oxygen,nitrogen, sulphur, or halo (particularly fluoro or chloro, especiallyfluoro) atom. For example, the linker component(s) may be or compriseone or more, suitably two or more, groups selected from halide(preferably fluoro), amino, cyano, imino, enamino, (1-6C)alkylamino,di-[(1-6C)alkyl]amino, tri-[(1-6C)alkyl]amino, oxo, oxide, hydroxide(OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy, (2-6C)alkynyloxy, formyl,carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl, (2-6C)alkanoyloxy,sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio, (2-6C)alkenylthio,(2-6C)alkynylthio, thiocarbonyl, heterocyclyl containing at least oneinternal heteroatom selected from nitrogen, oxygen or sulphur,heteroaryl containing at least one internal hetero atom selected fromnitrogen, oxygen or sulphur (e.g. pyridyl), or (where appropriate) adeprotonated form or salt thereof; wherein any CH, CH₂, or CH₃ isoptionally substituted. Any of the aforementioned groups may be linkeddirectly to each other or indirectly linked via a [CORE] as definedherein to form a linker component.

Where a linker component is a single molecule, ion, or complexcomprising two or more co-ordinating moieties, each being capable ofaccepting one or more lone pairs of electrons, suitably each of the twoor more co-ordinating moieties comprises or consists of a Lewis acidicmetal atom (which may include boron or silicon), or a metal atomattached to a leaving group or substitutable ligand. For example, thelinker component(s) may be or comprise one or more, suitably two ormore, groups selected from a metal cation (e.g. a divalent metalcation), a Lewis acidic metal compound (suitably a Lewis acid metalcompound, such as AlCl₃, FeCl₃, ZnCl₂, etc., or a complexed derivativethereof), a Lewis acidic metal complex (suitably a Lewis acid or acomplex with one or more free co-ordination sites, such as where themetal center has fewer than 18 electrons in its valence shell), and/or ametal compound or complex comprising a leaving group or substitutableligand (suitably where the conjugate acid of said leaving group orsubstitutable ligand has a pKa in water at standard ambient temperatureand pressure less than or equal to 1, suitably less than or equal to 0,suitably less than or equal to −1, more suitably less than or equal to−5). Suitable metal cations may include divalent (e.g. alkaline earthmetal, transition metal (II), or Sn²⁺ cations), trivalent (e.g. Al³⁺,transition metal(III) or f-block metal(III) cations), or tetravalent(Sn⁴⁺, Pb⁴⁺, transition metal(IV) or f-block metal(IV) cations) cations,most suitably divalent cations. Suitably Lewis acidic compounds mayinclude boron compounds (e.g. boron halides, alkoxides, etc.), siliconcompounds (e.g. silane, silioxane, silicon halides, etc.), Lewis acidicmetal compounds (e.g. AlCl₃, FeCl₃, ZnCl₂, etc.). Suitable Lewis acidicmetal complexes or complexes comprising a leaving group or substitutableligand may include carboxylate complexes such as dimetallic carboxylatecomplexes (e.g. [M₂(O₂C—R)₄], where M may be Cu²⁺, Ru²⁺, Rh²⁺),trimetallic carboxylate complexes (e.g. [M₂M′O(O₂CR)₆], where M may be atrivalent metal ion, and M′ may be a divalent metal ion), hexametalliccarboxylate complexes (e.g. [M′₄M₂O₂(O₂CR)₁₂] where M may be a trivalentmetal ion, and M′ may be a divalent metal ion), a dodecametallic complex(e.g. [Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆] where chp=6-chloro-2-pyridonate),metal compounds whose metal center is bonded to a leaving group (e.g. ahalide such as chloride, e.g. AlCl₃), metal complexes whose metalcentre(s) are co-ordinated with a substitutable ligand such as halide,water, a solvent such as THF, pyridine, or even carboxylate. Any of theaforementioned groups may be linked directly to each other or indirectlylinked via a [CORE] as defined herein to form a linker component.

Suitably the two or more co-ordinating moieties are capable ofco-ordinating with two different electron donating or electron acceptingspecies or complexes—for instance, the co-ordinating moieties aresuitably sufficiently distal to allow each to independently bond to aseparate species or complex. Co-ordinating moieties may be capable ofco-ordinating directly with (one of) the metal center(s) of the primaryand/or additional metal complex(es) and/or may be capable ofco-ordinating with (one of) the ligands associated with the primaryand/or additional metal complex(es).

Where a linker component is a molecule, ion, or complex defined byFormula IV, the [CORE] may comprise one or more co-ordinating groups,but suitably any co-ordinating group present within the [CORE] are(substantially) unavailable for co-ordination with any species orcomplexes external to the linker component. In some embodiments, the[CORE] may be absent altogether and Q and the one or more W groups aredirectly linked to each other.

The [CORE] may be any suitable core allowing the Q group to co-ordinatewith a primary metal complex whilst simultaneously allowing the or eachW group to co-ordinate with either another primary metal complex or withan additional metal complex.

The [CORE] may comprise a single core group to which the Q group and theor each of the W group(s) are commonly attached. As such, the [CORE] maybe a divalent or multivalent core group (the valency of which depends onthe value of w). Such a single core group (particularly applicable tolinker component(s) with electron pair-donating capability) may beselected from:

-   -   a) a divalent or multivalent optionally substituted acyclic core        group (e.g. optionally substituted (1-nC)alkylene,        (1-nC)alkenylene, (1-nC)alkynylene optionally comprising one or        more intervening heteroatoms or intervening        heteroatom-containing moieties, i.e. where heteroroatoms or        heteroatom-containing moieties are interspersed within the        carbon chain);    -   b) a divalent or multivalent cyclic or polycyclic core group,        for example, an optionally substituted cyclocarbon (e.g.        cycloalkane), heterocycle (e.g. morpholine), arene (benzene,        naphthalene), or heteroarene (pyridine, imidazole, indole);    -   c) a divalent or multivalent core group comprising at least one        cyclic or polycyclic group (e.g. optionally substituted        cyclocarbon, heterocycle, arene, or heteroarene) linked to one        or more acyclic moieties and/or cyclic or polycyclic        moieties; d) a divalent or multivalent macrocyclic core group        (which macrocyclic group may itself comprise one or more        optionally substituted cyclocarbyl, heterocyclyl, aryl, and/or        heteroaryl groups) (e.g. porphyrin or phthalocyanine).

A single core group may itself be or comprise a core metal complex orcore cation-centred complex. Where a single core group is or comprises acore metal complex, suitably said core metal complex comprises a coreligand and at least one core metal species (suitably a central metalion, such as Mg²⁺). Suitably the core ligand comprises one or more atomsor groups (especially electron pair-donating atoms, such as nitrogen,oxygen, and/or sulphur) which are co-ordinated to one or more metalions, for instance a central metal ion (e.g. Mg²⁺). For example, amacrocyclic single core group may be or comprise a divalent ormultivalent:

or a salt thereof;or may be a divalent or multivalent complex or salt thereof, such as:

wherein M^(x+) may be any suitable metal cation, especially a divalentmetal cation, such as Mg²⁺.

The linker component may comprise a single core, and may be selectedfrom the group including a bridging di-imine (e.g. 4, 4′-bipyridyl,1,2-dipyridylethene, 1,4-dipyridyltetrazine), a macrocycle (e.g.porphyrin or phthalocyanine) substituted with two or more pyridyl groups(i.e. a poly-pyridyl compound).

Where the [CORE] comprises a single core group, such as that definedabove, the linker component suitably comprises Q and W groups withelectron pair-donating co-ordinating moieties, such as those containingone or more heteroatoms, such as nitrogen, oxygen, and/or sulphur.However, it will be understood by the skilled person that a single coregroup may itself comprise one or more, suitably two or more,co-ordinating moieties (e.g. such as those containing one or moreheteroatoms, such as nitrogen, oxygen, and/or sulphur) which maythemselves be connected to Q and/or W groups which comprise electronpair-accepting moieties.

Suitably, each electron pair-donating Q and/or W group is selected fromany suitable group comprising an internal or external heteroatom bearinga lone pair of electrons. Most suitably, the or each electronpair-donating Q and/or W group is independently selected from optionallysubstituted heterocyclyl, heteroaryl, heterocyclyl(1-6C)alkyl,heteroaryl(1-6C)alkyl, or is selected from (1-12C)alkyl, (1-12C)alkenyl,(1-12C)alkynyl, (3-8C)cycloalkyl, (3-8C)cycloalkenyl,(1-3C)alkyl(3-8C)cycloalkyl, (1-3C)alkyl(3-8C)cycloalkenyl, aryl,(1-3C)alkylaryl, or aryl(1-3C)alkyl, substituted with one or more basicor chelating groups, for example, amino, alkylamino, dialkylamino,hydroxyl, (1-6C)alkoxy, carbonyl, immino, thio, thiocarbonyl, etc. In anembodiment, the or each electron pair-donating Q and/or W group isindependently selected from pyridyl, aminophenyl,N-(1-3C)alkylaminophenyl, N,N-di(1-3C)alkylaminophenyl, most suitablypyridyl, most suitably 4-pyridyl. For instance, in a particularembodiment, the linker is:

Suitably each pyridyl moiety is capable of co-ordinating with a primarymetal complex.

The [CORE] may comprise a plurality of core groups which are indirectlylinked together to form the [CORE] via the Q group and/or one or more ofthe or each of the W group(s). Such a [CORE] is especially relevantwhere one or more of the Q and/or W groups are metal-centered (which inthis case includes boron- and silicon-centered as well as standardmetal-centered; e.g. to provide a lewis acid/electron pair-acceptingco-ordinating group). Each of such core groups may be independentlyselected from:

-   -   a) a single atom, molecule, ion, or complex containing a single        co-ordinating moiety capable of donating two or more lone pairs        of electrons (e.g. O²⁻, oxo);    -   b) a single molecule, ion, or complex (e.g. a multiple        heteroatom-containing optionally substituted acyclic, cyclic,        polycyclic, or macrocyclic molecule) comprising two or more        co-ordinating moieties each capable of independently donating an        electron lone pair (e.g. internal heteroatoms, such as nitrogen,        oxygen, or sulphur, or external heteroatoms borne by optional        substituents) (e.g. carboxylate).

For instance, each core group may be independently selected from asingle atom, molecule, ion, or complex that comprises or consists of anoxygen, sulphur, or halo (particularly fluoro or chloro, especiallyfluoro) atom; most suitably halide (preferably fluoro), oxo, oxide,hydroxide (OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy, (2-6C)alkynyloxy,formyl, carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl,(2-6C)alkanoyloxy, sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio,(2-6C)alkenylthio, (2-6C)alkynylthio, thiocarbonyl, heterocyclylcontaining at least one internal heteroatom selected from oxygen orsulphur, or (where appropriate) a deprotonated form or salt thereof;wherein any CH, CH₂, or CH₃ is optionally substituted.

For instance, each core group may be independently selected from asingle molecule, ion, or complex comprising two or more co-ordinatingmoieties that comprise or consist of an oxygen, nitrogen, sulphur, orhalo (particularly fluoro or chloro, especially fluoro) atom; mostsuitably that comprise or consist of two or more groups selected fromhalide (preferably fluoro), amino, cyano, imino, enamino,(1-6C)alkylamino, di-[(1-6C)alkyl]amino, tri-[(1-6C)alkyl]amino, oxo,oxide, hydroxide (OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy,(2-6C)alkynyloxy, formyl, carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl,(2-6C)alkanoyloxy, sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio,(2-6C)alkenylthio, (2-6C)alkynylthio, thiocarbonyl, heterocyclylcontaining at least one internal heteroatom selected from nitrogen,oxygen or sulphur, heteroaryl containing at least one internal heteroatom selected from nitrogen, oxygen or sulphur (e.g. pyridyl), or (whereappropriate) a deprotonated form or salt thereof; wherein any CH, CH₂,or CH₃ is optionally substituted.

In a particular embodiment, each core group may be independentlyselected from a biLIG¹ group as defined herein, a biLIG² group asdefined herein, or an optLIG¹ group as defined herein. In a particularembodiment, each core group is independently selected from a biLIG¹group as defined herein or a biLIG² group as defined herein, mostsuitably a biLIG¹ group. Most suitably, the, each, or all of the coregroups are a carboxylate or carboxylic acid, most suitably a carboxylateor carboxylic acid defined by the formula —O₂CR_(B1) or defined by theformula —O₂CR_(B2) (or R_(B2)CO₂—), wherein R_(B1) and R_(B2) aresuitably as defined herein, though most suitably R_(B1) is (1-5C)alkylmost suitably R_(B2) is pyridyl, aminophenyl, N-(1-3C)alkylaminophenyl,N,N-di(1-3C)alkylaminophenyl,

Suitably, where [CORE] comprises a plurality of core groups, the coregroups are the same.

By way of example, a linker whose [CORE] comprises a plurality of coregroups may be defined by:

wherein each [core] is a core group independently defined as herein; andW and Q are electron pair-accepting Q and/or W groups as defined herein,and w is as defined herein.

Suitably, the or each electron pair-accepting Q and/or W group is asingle atom, molecule, ion, or complex containing a co-ordinating moietycapable of accepting one or more, suitably two or more lone pairs ofelectrons. Suitably the relevant co-ordinating moiety comprises orconsists of a Lewis acidic metal atom (which may include boron orsilicon), or a metal atom attached to a leaving group or substitutableligand. For example, the co-ordinating moiety may be or comprise a groupselected from a metal cation (e.g. a divalent metal cation), a Lewisacidic metal compound (suitably a Lewis acid metal compound, such asAlCl₃, FeCl₃, ZnCl₂, etc.), a Lewis acidic metal complex (suitably aLewis acid or a complex with one or more free co-ordination sites, suchas where the metal center has fewer than 18 electrons in its valenceshell), and/or a metal compound or complex comprising a leaving group orsubstitutable ligand (suitably where the conjugate acid of said leavinggroup or substitutable ligand has a pKa in water at standard ambienttemperature and pressure less than or equal to 1, suitably less than orequal to 0, suitably less than or equal to −1, more suitably less thanor equal to −5). Suitable metal cations may include divalent (e.g.alkaline earth metal, transition metal (II), or Sn²⁺ cations), trivalent(e.g. Al³⁺, transition metal(III) or f-block metal(III) cations), ortetravalent (Sn⁴⁺, Pb⁴′, transition metal(IV) or f-block metal(IV)cations) cations, most suitably divalent cations. Suitably Lewis acidicmetal compounds may include boron compounds (e.g. boron halides,alkoxides, etc.), silicon compounds (e.g. silane, silioxane, siliconhalides, etc.), Lewis acidic metal compounds (e.g. AlCl₃, FeCl₃, ZnCl₂,etc.). Suitable Lewis acidic metal complexes or complexes comprising aleaving group or substitutable ligand may include carboxylate complexessuch as dimetallic carboxylate complexes (e.g. [M₂(O₂C—R)₄], where M maybe Cu²⁺, Ru²⁺, Rh²⁺), trimetallic carboxylate complexes (e.g.[M₂M′O(O₂CR)₆], where M may be a trivalent metal ion, and M′ may be adivalent metal ion), hexametallic carboxylate complexes (e.g.[M′₄M₂O₂(O₂CR)₁₂] where M may be a trivalent metal ion, and M′ may be adivalent metal ion), a dodecametallic complex (e.g.[Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆] where chp=6-chloro-2-pyridonate), metalcompounds whose metal center is bonded to a leaving group (e.g. a halidesuch as chloride, e.g. AlCl₃), metal complexes whose metal centre(s) areco-ordinated with a substitutable ligand such as halide, water, asolvent such as THF, pyridine, or even carboxylate. However, inpreferred embodiments, the or each electron pair-accepting Q and/or Wgroup is independently a metal cation, suitably independently a divalentor trivalent metal cation, suitably as defined herein. Suitably Q may bedifferent from at least one W group. Suitably, all Q and W groups may bethe same.

In a particular embodiment, the linker is selected from:

-   -   dimetallic carboxylate complexes (e.g. [M₂(O₂C^(R))₄] where        M=Cu, Ru, Rh);    -   trimetallic carboxylate complexes (e.g. [M₂M′O(O₂C^(R))₆] where        M=a trivalent metal ion, M′=a divalent metal ion;    -   hexametallic carboxylate complexes (e.g. [M′₄M₂O₂(O₂CR)₁₂] where        M=a trivalent metal ion, M′ a divalent metal ion);    -   a dodecametallic complex such as [Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆]        where chp=6-chloro-2-pyridonate.

The linker component(s) may be independently selected from:

-   -   A monoLIG¹ group as defined herein;    -   a biLIG² group as defined herein;    -   an optLIG¹ group as defined herein;    -   a metal complex;    -   a macrocycle optionally co-ordinate to a metal;    -   dimetallic carboxylate complexes (e.g. [M₂(O₂C^(R))₄] where        M=Cu, Ru, Rh);    -   trimetallic carboxylate complexes (e.g. [M₂M′O(O₂CR)₆] where M=a        trivalent metal ion, M′=a divalent metal ion;    -   hexametallic carboxylate complexes (e.g. [M′₄M₂O₂(O₂CR)₁₂] where        M=a trivalent metal ion, M′ a divalent metal ion);    -   a dodecametallic complex such as [Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆]        where chp=6-chloro-2-pyridonate.    -   a terminal ligand, e.g. H₂O, pyridine or a substituted pyridine,        where n=1.    -   bridging di-imine, e.g. 4,4′-bipyridyl, 1,2-dipyridylethene,        1,4-dipyridyltetrazine    -   other poly-pyridyl ligands, including pyridyls substituted        around macrocycles such as porphyrins or phthalocyanines.

Linker may have other solvates or ligands (suitably inert) associatedtherewith, or may be a salt.

Optional Base Polymeric Component

The eBeam resist composition may comprise a base polymeric component,which is suitably a resist material (e.g. a resist polymer), and thussuitably a radiation-sensitive material which undergoes transformationupon exposure to the relevant radiation (e.g. Ebeam). Suitably basepolymeric component that is radiation-exposed (and thus “transformed”)has different solubility properties to base polymeric component that isunexposed (and thus “untransformed”), suitably such that selectiveexposure of the base polymeric component provides a solubilitydifferential allowing for subsequent “development” and selective removalof the exposed or unexposed part(s) of the base polymeric component(depending on whether the resist is positive or negative tone).

The base polymeric component may be any suitable base polymericcomponent. A variety of base polymeric components are known to thoseskilled in the art for use in eBeam resist compositions, and any ofthese may be suitably used (optionally tuned accordingly) depending onthe desired properties of the eBeam resist composition. In a particularembodiment, the base polymeric component is an Ebeam resist basepolymeric component.

The base polymeric component suitably has a density greater than orequal to 0.8 g/cm³, suitably greater than or equal to 0.9 g/cm³,suitably greater than or equal to 0.95 g/cm³, suitably greater than orequal to 1.0 g/cm³. The base polymeric component suitably has a densityless than or equal to 2 g/cm³, suitably less than or equal to 1.5 g/cm³,suitably less than or equal to 1.3 g/cm³, suitably less than or equal to1.2 g/cm³. Suitably the base polymeric component has a lower densitythan the secondary electron generator, suitably at least 1.0 g/cm³lower, suitably at least 2.0 g/cm³ lower.

Suitably the base polymeric component may be selected from the groupincluding: poly(methylmethacrylate), poly(1-naphthyl methacrylate),poly(1-vinylnaphthalene), poly(2,6-napthalenevinylene),poly(2-chlorostyrene), poly(2,6-dichlorostyrene),poly(2-vinylthiophene), poly(N-vinylphthalimide), poly(vinyl phenylsulphide), polyhydroxystyrene or any suitable mixture or copolymerthereof.

In a particular embodiment, the base polymeric component is poly(methylmethacrylate) (PMMA), suitably with a weight average molecularweight between 10-1500 kDalton (kDa), suitably between 50-1200, suitably100-1100. Suitably PMMA or any other suitable base polymeric componentis used in conjunction with an appropriate cross-linking agent (e.g.dipentaerythriolpentaacrylate DPEPA or pentaerythritoltetraacrylate(PET)), suitably to form a particularly advantageous negative eBeamresist composition.

Suitably the base polymeric component constitutes at least 1 wt % of theeBeam resist composition, suitably at least 5 wt %, suitably at least 10wt %, suitably at most 70 wt %, suitably at most 55 wt %.

Secondary Electron Generator

The eBeam resist composition may suitably further comprise of asecondary electron generator, suitably one or more secondary electorngenerators.

Co-pending application PCT/GB2015/050884 (filed on 24 Mar. 2015 by thesame Applicants as the present application), which is herebyincorporated by reference, describes eBeam resist compositionscomprising such secondary electron generators, and provides extensiveexperimental data, models (e.g. Monte-Carlo models), and explanationsillustrating the salient points and key parameters (such ascomparatively high Z_(eff), comparatively high densities, etc.)identified by the inventors as suitably important for viable secondaryelectron generators. As such, the secondary electron generator in thecontext of the present invention may be any secondary electron generatordescribed in this co-pending application for use in eBeam resistcompositions. Furthermore, relationships between the secondary electrongenerator and other components that may also be present within the eBeamresist compositions of the present invention (e.g. base polymericcomponent) also apply to such components of the invention.

For the avoidance of doubt or ambiguity, some key passages of theaforementioned co-pending application are hereby substantiallyreplicated.

The inclusion of a secondary electron generator within an eBeam resistcomposition allows the generation (and/or amplification) of secondaryelectrons (something those skilled in the art historically tried toavoid) to be thoroughly exploited during exposure of a resist. Insteadof viewing the production of secondary electrons as problematic, andtrying to quell them, some resist compositions of the present inventiondeliberately include a secondary electron generator to promote secondaryelectron generation. The energy of the secondary electrons is harnessedto allow for increased exposure sensitivity of a resist composition orcoating thereof; decreased energy and/or intensity of incident exposureradiation (which in itself reduces damage to the resist from primaryradiation); increased write-speed during electron beam exposure;decreased resist-coating thickness; increased aspect ratio; and/orincreased resolution in the patterning of the resists.

An additional advantage of the present invention is that any potentiallyadverse effects of extra secondary electron generation can be mitigatedor controlled by the anti-scattering compounds/complexes. As such, theanti-scattering compound/complex and secondary electron generator cansynergistically balance once another to allow for optimization of eBeamresist compositions.

This disclosure, in conjunction with the aforementioned co-pendingapplication, equips the skilled person to judiciously select appropriatesecondary electron generators, with sufficient secondary electrongenerating potential, for any particular resist system. The examples anddata provided herein and in the aforementioned co-pending application(especially the validated predictive models described therein), providea highly credible demonstration of the broad applicability of theinvention to a range of secondary electron generators. Typically, thesecondary electron generators of the invention have one or moredesirable characteristics (e.g. sufficient Z or Zeff, sufficientdensity, sufficient “stopping power”/innovation potential, solubility incustody solvent(s) etc).

The technology of the present invention may be adapted for use witheither positive or negative tone resists since, generally speaking, apositive resist can be modified to produce a negative resist bytechniques well known in the art (e.g. adding a cross-linking agent).Such systems are also described in the aforementioned co-pendingapplication.

Suitably the “effective atomic number (Z_(eff))” is calculated as:

Z _(eff)=Σα_(i) Z _(i)

Where Z_(i) is the atomic number of the ith element in the compound, andα_(i) is the fraction of the sum total of the atomic numbers of allatoms in the compound (i.e. the total number of protons in the compound)constituted by said ith element.

The secondary electron generator suitably yields secondary electrons,suitably upon impact with primary electrons from an electron beam.

The secondary electron generator suitably generates secondary electrons,as ionization products, in response to exposure to primary electronsfrom an electron beam.

The secondary electron generator and/or compound(s) thereof bydefinition yield more secondary electrons (i.e. have a higher secondaryelectron omission yield) than any antiscattering component/complexand/or any base polymeric component, suitably at least by a factor of 2,suitably at least by a factor of 3, suitably at least by a factor of 4.

The secondary electron generator suitably is or comprises a compoundhaving an effective atomic number (Z_(eff)) greater than or equal to 15(where optionally the Z_(eff) calculation excludes any solvates, havinga boiling point less than or equal to 150° C. at 100 kPa pressure,associated with said compound, suitably any solvates having a boilingpoint less than or equal to 120° C. at said pressure, suitably ≦105° C.at said pressure). Suitably this Z_(eff) is greater than or equal to 18,suitably greater than or equal to 23, suitably greater than or equal to25, suitably greater than or equal to 30, suitably greater than or equalto 32, suitably greater than or equal to 40. Suitably this Z_(eff) isless than or equal to 70, suitably less than or equal to 66, suitablyless than or equal to 61, suitably less than or equal to 60, suitablyless than or equal to 55. The secondary electron generator orcompound(s) thereof suitably has a higher Z_(eff) than the basepolymeric component, suitably at least 10 units higher, suitably atleast 20 units higher, suitably at least 30 units higher.

Suitably, the secondary electron generator is or comprises a compoundhaving a molecular weight less than or equal to 500 g/mol.

The secondary electron generator suitably is or comprises a metalcompound. It cannot be or comprise an elemental metal (i.e. metal(0)).In fact, the resist composition is suitable (substantially) free of anymetal (0)). Suitably any metal species of the metal compound are metalions.

References to the secondary electron generator or compound(s) thereofgenerally relate to the pre-mixed (i.e. prior to mixing with othercomponents of the resist composition) form thereof (e.g. in terms of anycationic-anionic associations in relevant metal compound(s)), andsuitably also relate to the pre-coated, pre-cured, pre-exposed,pre-developed form thereof. It will be appreciated by those skilled inthe art that, upon mixing with other components of the resistcomposition (and/or after coating, curing, exposing, and/or developing),any relevant cations and anions of metal compound(s) may, in someembodiments (though not all), dissociate and possibly become associatedwith other counterions and/or ligands. Therefore, references to an eBeamresist composition (or indeed a coating, or a cured-, exposed-, ordeveloped-product thereof) suitably indicates an eBeam resistcomposition (or a coating, or a cured-, exposed-, or developed-productthereof) “formed by” (or derived from) mixing the relevant compound(s)with any other ingredients of the eBeam resist composition or “formedby” curing, exposing, and/or developing the relevant product. It isstraightforward for those skilled in the art, using standard techniques,to determine the input compound(s) from a eBeam resist composition or acoated, cured-, exposed-, or developed-product thereof.

The compound(s) of the secondary electron generator suitably has adensity greater than that of the base polymeric component. Thecompound(s) of the secondary electron generator suitably has a densitygreater than or equal to 1.7 g/cm³, suitably greater than or equal to 2g/cm³, suitably greater than or equal to 2.5 g/cm³, suitably greaterthan or equal to 3 g/cm³, suitably greater than or equal to 4 g/cm³,more suitably greater than or equal to 4.1 g/cm³, suitably greater thanor equal to 4.5 g/cm³, more suitably greater than or equal to 4.7 g/cm³,most suitably greater than or equal to 5 g/cm³. The compound(s) of thesecondary electron generator suitably has a density less than or equalto 9 g/cm³, suitably less than or equal to 8.5 g/cm³, suitably less thanor equal to 8 g/cm³. In a particular embodiment, the compound(s) of thesecondary electron generator suitably has a density between 3.5 and 8.3g/cm³. Suitably the density is at least 2 times higher than the densityof the antiscattering compound/complex and/or any base polymericcomponent, suitably at least 3 times higher.

Suitably, the compound(s) of the secondary electron generator have amean ionization potential (i.e. employing the “stopping power” meaning,suitably as provided by the well-known Bethe equation and the MonteCarlo model described in the aforementioned co-pending application) of≧200 eV, suitably ≧500 eV.

Suitably the compound(s) has a low mean free path (λ)—i.e. the distancebetween successive electron collisions is low. Suitably the compound(s)has a lower mean free path (λ) than the base polymeric component.Suitably the compound(s) of the secondary electron generator has anelastic mean free path of less than or equal to 900 nm, suitably lessthan or equal to 100 nm, suitably less than or equal to 50 nm, suitablyless than or equal to 825 nm. Suitably the compound(s) of the secondaryelectron generator has an inelastic mean free path of less than or equalto 825 nm.

Suitably the compound(s) has a high elastic scattering cross-section(σ)—i.e. the chance of a collision is high. Suitably the compound(s) hasa higher elastic scattering cross-section (σ) than the base polymericcomponent. Suitably the compound(s) of the secondary electron generatorhas an elastic scattering cross-section (σ) of greater than or equal to7×10⁻⁹ cm/atom, suitably greater than or equal to 1×10⁻¹⁸, suitablygreater than or equal to 2×10⁻¹⁷, suitably greater than or equal to4×10⁻¹⁸, suitably greater than or equal to 7×10⁻¹⁸. Suitably theantiscattering compound/complex and/or any base polymeric component (orthe primary component thereof) has an elastic scattering cross-section(a) of less than or equal to 1×10⁻¹⁸ cm/atom, suitably less than orequal to 7×10⁻¹⁹ cm/atom. In a particular embodiment, the compound(s) ofthe secondary electron generator has an elastic scattering cross-section(c) of greater than or equal to 7×10⁻¹⁹ cm/atom whereas theantiscattering compound/complex and/or any base polymeric component (orthe primary component thereof) has an elastic scattering cross-section(a) of less than or equal to 7×10⁻¹⁹ cm/atom. In a particularembodiment, the compound(s) of the secondary electron generator has anelastic scattering cross-section (σ) of greater than or equal to 2×10⁻¹⁸cm/atom whereas the antiscattering compound/complex and/or any basepolymeric component (or the primary component thereof) has an elasticscattering cross-section (σ) of less than or equal to 7×10⁻¹⁹⁻cm/atom.

Any, some, or all of the definitions relating to any of the aforesaidparameters (e.g. Z_(eff), density, mean free path, scatteringcross-sectioning, mean ionization potential/stopping power, electronemission yield) may suitably relate to a form of the compound(s) whichexcludes any solvates having a bp ≦150° C. at 100 kPa pressure, suitably≦120° C., suitably ≦105° C., e.g. excluding hydrates. This is reasonablesince such solvates may be removed during processing.

Suitably any metal compound(s) of the secondary electron generatorcomprises a metal species which has an oxidation state of +1 or higher,suitably +2 or higher, suitably +3 or higher. Suitably any metalcompound(s) of the secondary electron generator comprises a metalspecies which has an oxidation state of +4 or lower. Suitably any metalcompound(s) of the secondary electron generator comprises a metalspecies which has an oxidation state of +3.

Suitably any metal compound(s) of the secondary electron generatorcomprises a single metal species or otherwise a predominant metalspecies (i.e. metal species constituting at least 50 wt % of the totalmetal species, suitably at least 80 wt %, suitably at least 90 wt %,suitably at least 95 wt %). The metal species or metal ions (whethersingle or predominant) of such metal compound(s) of the secondaryelectron generator suitably have an oxidation state of +1 or higher,suitably +2 or higher, suitably +3 or higher. The metal species or metalions (whether single or predominant) of such metal compound(s) of thesecondary electron generator suitably have an oxidation state of +4 orlower. The metal species or metal ions (whether single or predominant)of such metal compound(s) of the secondary electron generator suitablyhave an oxidation state of +3. In an embodiment, the metal species ormetal ions of such metal compound(s) of the secondary electron generatorhave an oxidation state of +2.

Any metal compound(s) of the secondary electron generator suitablycomprises a metal species (or a single or predominant metal species)having an atomic number (Z) greater than or equal to 21 (i.e. scandiumor heavier). Any metal compound(s) of the secondary electron generatorsuitably comprises a metal species (or a single or predominant metalspecies) having an atomic number (Z) greater than or equal to 22 (i.e.titanium or heavier). Any metal compound(s) of the secondary electrongenerator suitably comprises a metal species (or a single or predominantmetal species) having an atomic number (Z) greater than or equal to 39(i.e. yttrium or heavier). Any metal compound(s) of the secondaryelectron generator suitably comprises a metal species (or a single orpredominant metal species) having an atomic number (Z) greater than orequal to 49 (i.e. indium or heavier). Any metal compound(s) of thesecondary electron generator suitably comprises a metal species (or asingle or predominant metal species) having an atomic number (Z) greaterthan or equal to 57 (i.e. lanthanum or heavier). Any metal compound(s)of the secondary electron generator suitably comprises only metalspecies (or a single or predominant metal species) having an atomicnumber (Z) less than or equal to 82 (i.e. lead or lighter). Any metalcompound(s) of the secondary electron generator suitably comprises onlymetal species (or a single or predominant metal species) having anatomic number (Z) less than or equal to 80 (i.e. mercury or lighter).The metal species of the metal compound(s) may suitably be a d-block,p-block, or f-block metal species, or a mixture thereof. Suitably themetal compound(s) is non-radioactive.

Suitably the secondary electron generator is or comprises a metalhalide, or a complex thereof (e.g. HAuCl₄). Suitably the secondaryelectron generator is a metal (I), metal (II), metal (III), or metal(IV) halide, or a complex thereof. Suitably the secondary electrongenerator is a metal (III) halide or a metal(l) halide, or a complexthereof. Suitably the secondary electron generator is a metal chloride,suitably a metal (I), metal (II), metal (III), or metal (IV) chloride.Suitably the secondary electron generator is a metal chloride, suitablya metal (I) or a metal (III) chloride.

The secondary electron generator may be a metal(II) halide (e.g. HgCl₂),or a complex thereof. In a particular embodiment, the secondary electrongenerator is a metal(II) chloride.

The secondary electron generator may suitably be selected from the groupincluding, AlCl₃, TiCl₃, TiCl₄, CrCl₃, GaCl₃, YCl₃, MoCl₃, AgCl, InCl₃,SbCl₃ HfCl₃ TaCl₃, WCl₃, OsCl₃, IrCl₃, AuCl, AuCl₃, HAuCl₄, HgCl₂,CeCl₃, NdCl₃ ErCl₃, OsO₄ or any suitable complex (including any suitablesalt or salt complex) thereof. In a particular embodiment, the metalcompound is chloroauric acid (hydrogen chloroaurate, HAuCl₄) or thehydrate thereof (HAuCl₄.4H₂O). In another embodiment, the metal compoundis sodium chloroaurate (NaAuCl₄) or a hydrate thereof (e.g.NaAuCl₄.2H₂O). In a particular embodiment, the metal compound is amercury dichloride.

In a particular embodiment, the secondary electron generator is agold-based compound (preferably a compound comprising gold(III)species). In a particular embodiment, the secondary electron generatoris a mercury-based compound (preferably a compound comprisingmercury(II) species). In a particular embodiment, the secondary electrongenerator is an indium-based compound (preferably a compound comprisingindium(III) species). In a particular embodiment, the secondary electrongenerator is an yttrium-based compound (preferably a compound comprisingyttrium (III) species). In a particular embodiment, the secondaryelectron generator is a titanium-based compound (suitably a compoundcomprising titanium (IV) species).

The secondary electron generator is suitably an anhydrous metalcompound. Suitably the metal compound of the secondary electrongenerator has a water content of less than or equal to 0.1 wt %,suitably less than or equal to 0.05 wt %, suitably less than or equal to0.01 wt %, suitably less than or equal to 0.001 wt %. It is thought thathigher water content can have an adverse effect on the secondaryelectron generation capacity, possible by virtue of a density effect.However, in some embodiments, a secondary electron generator metalcompound may be a solvate, e.g. a hydrate.

The secondary electron generator is suitably non-particulate, especiallywithin the eBeam resist composition where it is suitably dissolvedwithin the solvent. The secondary electron generator is suitably solublein the eBeam resist composition. This enables its uniform distributionin the ultimately applied resist coating, and may facilitatemetal-organic nanocomposite coating formation.

Any of the aforementioned metal compound(s) may be a complex thereof.

Suitably the secondary electron generator constitutes at least 1 wt % ofthe resist composition, suitably at least 5 wt %, suitably at least 10wt %, suitably at most 70 wt %, suitably at most 55 wt %.

The secondary electron generator may be a single compound (or complex)or a mixture of compounds (and/or complexes). References herein to “asecondary electron generator” may refer to a single compound, which isthus designated as the secondary electron generator.

Though the one or more secondary electron generators may be considered aconstituent part (or ingredient of) the eBeam resist composition and bedefined by reference to the “secondary electron ingredient” used (i.e.added as an ingredient) in the formation of the overall resistcomposition, the skilled person will understand that chemical reactionsand/or molecular associations (e.g. co-ordination/dative bonds) may meanthat the secondary electron generator exists in a different form withinthe resist composition (e.g. co-ordinated within a complex) than priorto its inclusion therein. In fact, in many preferred embodiments, withinthe resist composition itself the secondary electron generator exists ina co-ordinated form and forms a complex with one or more otheringredients of the resist composition. For instance, mercury dichloridemay become associated and/or co-ordinate with the antiscatteringcompound/complex.

Most suitably, the antiscattering compound/complex forms one or moredative bonds with the secondary electron generator. Suitably, one ormore of the ligands, in particularly one or more lone-pair-bearingheteroatoms thereof, co-ordinates with the secondary electron generator(preferably to a central metal ion thereof). In particular embodiments,the secondary electron generator is co-ordinated to the primary metalcomplex (and/or additional metal complex), suitably attached to theoutside thereof. Where there are a plurality of primary metal complexes(or additional metal complexes) within the antiscatteringcompound/complex, suitably each primary metal complex is co-ordinated toone or more secondary electron generator(s).

Such an intimate association between a secondary electron generator andan anti-scattering compound can radically improve the overallperformance and balance of an eBeam resist composition. In this manner,the antiscattering compound/complex may serve its function, includinglocalizing of the incident eBeam, whilst local secondary electrongenerator(s) can improve overall write speeds without undulycompromising resolution.

Suitably, a molar ratio of secondary electron generator toanti-scattering compound is a function of the stoichiometry of theprimary metal complex within the anti-scattering compound, especiallywhere the secondary electron generator becomes bonded to the primarymetal complex or a ligand thereof. As such, the molar ratio of thesecondary electron generator to primary metal complex(es) is suitablybetween 0.01:1 and 12:1, more suitably between 0.5:1 and 8:1, mostsuitably between 1:1 and 4:1.

Scattering Compound

The eBeam resist composition may suitably further comprise of ascattering compound, suitably one or more scattering compounds.

The inclusion of a scattering compound within an eBeam resistcomposition allows electrons to be scattered but in a controlled mannerby virtue of the antiscattering compound. Suitably, the eBeam focusingeffect of the antiscattering compound acts synergistically with thescattering compound to optimize the balance between focusing andscattering to thereby achieve high resolution imaging at reasonablewrite-speeds.

The scattering compound suitably is or comprises a compound having aneffective atomic number (Z_(eff)) less than or equal to 15 (whereoptionally the Z_(eff) calculation excludes any solvates, having aboiling point less than or equal to 150° C. at 100 kPa pressure,associated with said compound, suitably any solvates having a boilingpoint less than or equal to 120° C. at said pressure, suitably ≦105° C.at said pressure). Suitably this Z_(eff) is less than or equal to 10,suitably less than or equal to 7.

The scattering compound m suitably has a density greater than or equalto 0.8 g/cm³, suitably greater than or equal to 0.9 g/cm³, suitablygreater than or equal to 0.95 g/cm³, suitably greater than or equal to1.0 g/cm³. The base polymeric component suitably has a density less thanor equal to 2 g/cm³, suitably less than or equal to 1.5 g/cm³, suitablyless than or equal to 1.3 g/cm³, suitably less than or equal to 1.2g/cm³. Suitably the base polymeric component has a lower density thanthe secondary electron generator, suitably at least 1.0 g/cm³ lower,suitably at least 2.0 g/cm³ lower.

Suitably the scattering compound is an organic compound. Suitably thescattering compound comprises carbon and hydrogen atoms.

Most suitably, the scattering compound comprises one or more atomscapable of datively co-ordinating with the anti-scatteringcompound/complex, suitably with a metal centre of the anti-scatteringcompound, most suitably with a metal centre of a primary metal complexand/or additional metal complex. Suitably, the scattering compoundcomprises one or more lone-pair bearing heteroatoms, for instance, oneor more heteroatoms selected from oxygen or nitrogen. The scatteringcompound may additional comprise one or more halogen atoms.

Most suitably, the scattering compound comprises one or moreelectron-containing π- and/or p-orbitals, suitably two or more, moresuitably three or more thereof. Suitable electron-containing p-orbitals,may include electron lone pair(s), for instance, such as those localizedon heteroatoms such as oxygen and/or nitrogen. Electron-containingπ-orbitals may, for example, include π-bonds or π-systems (whetheraromatic or non-aromatic). Such π-bonds may include those of alkeneand/or alkyne moieties. Such π-systems may include those ofoptionally-substituted phenyl moieties and such like. Such π-bonds andπ-systems are particularly appropriate for scattering electrons from aneBeam.

The combination of lone-pair-bearing heteroatoms alongside one or moreelectron containing π-bonds or π-systems (especially π-bonds, mostsuitably terminal π-bonds) is particular potent in the context of theinvention, since the combination increases the effective scatteringcross-section (essentially rendering them better attenae for primaryelectrons) and propensity for scattering whilst also increasing theability of the scattering compound to effectively co-ordinate to theantiscattering compound to thereby enable synergistic action between thetwo.

Suitably, the scattering compound comprises one or more alkene and/oralkyne moieties, suitably two or more thereof. Suitably, the scatteringcompound comprises one or more alkene moieties, suitably two or morethereof. Suitably, the scattering compound comprises one or moreterminal alkene moieties (i.e. at a chain terminus), suitably two ormore thereof.

Suitably, the scattering compound comprises one or more internal (i.e.non-terminal) lone-pair-bearing heteroatoms.

Suitably the scattering compound is an organic compound comprising twoor more alkene moieties, suitably two or more terminal alkene moieties.

In a particular embodiment the scattering compound is selected from thegroup consisting of: diallylamine, diallylamine, triallylamine, transtrans farnesyl bromide, Pentraerythritol tetraacrylate (PET). In aparticular embodiment, the scattering compound is selected from thegroup consisting of:

Though the one or more scattering compounds may be considered aconstituent part (or ingredient of) the eBeam resist composition and bedefined by reference to the “scattering compound ingredient” used (i.e.added as an ingredient) in the formation of the overall resistcomposition, the skilled person will understand that chemical reactionsand/or molecular associations (e.g. co-ordination/dative bonds) may meanthat the scattering compound exists in a different form within theresist composition (e.g. co-ordinated within a complex) than prior toits inclusion therein. In fact, in many preferred embodiments, withinthe resist composition itself the scattering compound exists in aco-ordinated form and forms a complex with one or more other ingredientsof the resist composition.

Most suitably, the antiscattering compound/complex forms one or moredative bonds with the scattering compound. Suitably, the scatteringcompound co-ordinates (suitably via electron lone pairs, for instanceresiding on a hetero atom thereof, and/or one or more pi-systemsthereof) with one or more of the metal centres, in particularly one ormore metal centres of a primary metal complex, of the antiscatteringcompound/complex. As such, suitably the scattering compound may beco-ordinated within a metal cage of the primary metal complex. Suchbinding within a primary metal complex is particularly useful inachieving an optimal balance between scattering, antiscattering, andfocusing. In particular embodiments, the scattering compound isco-ordinated to the primary metal complex (and/or additional metalcomplex), suitably attached to the inside thereof. Where there are aplurality of primary metal complexes (or additional metal complexes)within the antiscattering compound/complex, suitably each primary metalcomplex may be co-ordinated with one or more scattering compounds.

Such an intimate association between a secondary electron generator andan anti-scattering compound can dramatically improve the overallperformance and balance of an eBeam resist composition. In this manner,the antiscattering compound/complex may serve its function, includinglocalizing of the incident eBeam, whilst localized/harnessed scatteringcompound(s) can improve overall write speeds without unduly compromisingresolution.

Suitably, a molar ratio of scattering compound to anti-scatteringcompound is a function of the stoichiometry of the primary metal complexwithin the anti-scattering compound, especially where the scatteringcompound becomes bonded within the primary metal complex. As such, themolar ratio of the scattering compound to primary metal complex(es) issuitably between 0.01:1 and 2:1, more suitably between 0.5:1 and 1.5:1,most suitably about 1:1.

Suitably, any scattering compound is present within an eBeam resistcomposition (whether or not attached to the antiscattering agent) at aweight concentration of 0.5 to 40 wt %, more suitably 5 to 30 wt %, moresuitably 10 to 25 wt %, more suitably 15 to 20 wt %. Suitably, theweight ratio of any scattering compound to antiscattering compound (withor without an associated secondary electron generator) is between 10:1to 1:100, more suitably between 1:1 and 1:10, most suitably about 1:5.

Optional Additional Components

A cross-linking agent may be present in negative eBeam resistcompositions, or coatings or pattern layers derived therefrom,especially where a base polymeric component is present in addition tothe anti-scattering compound.

A cross-linking agent suitably facilitates formation of adeveloper-insoluble resist following radiation exposure. It is thoughtthat though the base polymeric component and/or the anti-scatteringcompound may undergo initial scission upon exposure to radiation,subsequent reaction(s) with the cross-linking agent may reconstitute thebase polymeric component and/or anti-scattering compound (at least to adegree) into a transformed component which is developer-insoluble,whilst the unexposed base polymeric component and/or anti-scatteringcompound may remain developer-soluble.

Any suitably cross-linking agent may be used, though most advantageouslythe cross-linking agent is judiciously selected for maximumcompatibility with the radiation source and the resist composition andthe components thereof.

In preferred embodiments, especially where eBeam radiation is usedexposing, the cross-linking agent is dipentaerythriolpentaacrylate(DPEPA) or pentaerythritoltetraacrylate (PET), or any other suitablemiscible multi-functional acrylate and/or mixtures thereof. Othercrosslinking agents include epoxies (SU8) or if the copolymer used isfor example polyhydroxystyrene a suitable photacid generator maybeemployed to bring about a solubility change.

Any suitable solvent system may be employed as a diluent for the eBeamresist composition. The solvent may, in fact, be a combination of one ormore solvents. As such, references herein to a solvent may, unlessstated otherwise, optionally include a mixture of solvents. Suitably thesolvent dissolves the (combination of) solute components of the eBeamresist composition to thereby form a solution. Suitably the solvent isused within the eBeam resist composition in a proportion which dissolvesthe (combination of) non-solvent components therein to thereby form asolution. The eBeam resist composition is suitably a solution.

The dilution level can be varied to suit the system, and will dependentirely on the combination of ingredients, any solubility constraints,and the desired dilution level (e.g. for optimal casting of the resist).Suitably, however, the weight ratio of solvent(s) to base polymericcomponent is between 10:1 and 100:1.

Suitably solvents include hexane, heptane, pentane, anisole, toluene,xylene, n-propanol, iso-propanol, acetone, dichloromethane, butylacetate, tetrahydrofuran, dimethylformamide, ethyl acetate, diethylether, or a combination thereof. In a particular embodiment, the solventincludes a non-polar organic solvent (suitably one that is substantiallyimmiscible with water, for example, hexane, toluene, heptanes), suitablyin a weight ratio of 1:1 to 1:100.

Specific Embodiments

Suitably, the anti-scattering compound comprises one or more, suitablytwo or more, polymetallic cages co-ordinated to a central linker. Inpreferred embodiments, the polymetallic cage(s) comprise two or moredifferent types of metal species, suitably two or more different metals.Suitably, the polymetallic cage(s) comprise at least one trivalent metalspecies (e.g. M¹ as above) and at least one divalent metal species (e.g.M² above). Suitably the trivalent metal species is or comprises Cr³⁺ andsuitably the divalent species is or comprises Ni²⁺. Suitably the ratioof Cr³⁺ to Ni²⁺ in the or each polymetallic cage is between 10:1 and2:1, more suitably between 9:1 and 6:1, most suitably about 7:1. Thepolymetallic cage(s) suitably comprise one or more bridging ligandswhich form a covalent bridge between two or more metal species withinthe cage(s)—most suitably the bridging ligands include carboxylate (orcarboxylic acid) ligands. Suitably the or each polymetallic cage isco-ordinated to a central linker via one or more metal species (suitablyvia just one metal species) of the polymetallic cage(s) (e.g. where thepolymetallic cage acts as a Lewis acid or electron-pair acceptor, andthe linker acts as a Lewis base or electron-pair donator); or the oreach polymetallic cage is co-ordinated to a central linker via one ormore of the ligand(s) of the polymetallic cage(s) (e.g. where thepolymetallic cage acts as a Lewis base or electron-pair donator, and thelinker acts as a Lewis acid or electron-pair acceptor).

In a particular embodiment, the anti-scattering compound comprises unitsdefined by a hybrid complex of Formula B:

(PMC)_(p)(LINK)_(l)

wherein:PMC is a polymetallic cage comprising a trivalent metal species M¹ and adivalent metal species M² in an M¹:M² molar ratio of between 10:1 and2:1 (suitably about 7:1), p is an even integer between 2 and 8; andwherein LINK is a linker component, suitably as defined herein, and l is1.

In a particular embodiment, PMC is selected from [M¹ _(x)M²_(y)(monoLIG¹)_(m1)(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)], [M¹ _(8-y)M²_(y)F₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)], or[Cr₇NiF₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]; and LINK is defined byQ-[CORE]-[W]_(w); wherein [CORE] comprises a plurality of core groupswhich are indirectly linked together to form the [CORE] via the Q groupand/or one or more of the or each of the W group(s), wherein one or moreof the Q and/or W groups are metal-centered to provide a lewisacid/electron pair-accepting co-ordinating group capable ofco-ordinating with lewis base/electron pair-donating co-ordinatinggroup(s) of the PMC. In a particular embodiment, LINK is selected fromany of the following:

-   -   dimetallic carboxylate complexes (e.g. [M₂(O₂C^(R))₄] where        M=Cu, Ru, Rh);    -   trimetallic carboxylate complexes (e.g. [M₂M′O(O₂CR)₆] where M=a        trivalent metal ion, M′=a divalent metal ion;    -   hexametallic carboxylate complexes (e.g. [M′₄M₂O₂(O₂CR)₁₂] where        M=a trivalent metal ion, M′ a divalent metal ion);    -   a dodecametallic complex such as [Ni₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆]        where chp=6-chloro-2-pyridonate.

In a particular embodiment, the anti-scattering compound is as definedin the specific embodiments above, wherein the primary metal complex isdefined by or comprise units defined by the Formula IIb:

[Cr₇NiF₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)];

wherein R_(B1), R_(B2), and b2 are as defined herein, though mostsuitably R_(B1) is t-butyl and R_(B2) if present is 4-pyridyl; andLINK is selected from the group including:

-   -   A dimetallic carboxylate complex (e.g. [M₂(O₂C^(R))₄] where M=a        divalent metal ion;    -   A dimetallic carboxylate complex (e.g. [MM′(O₂C^(R))₄]⁺ where        M=a divalent metal ion; M′=a trivalent metal ion;    -   A trimetallic carboxylate complex (e.g. [M₃O(O₂CR)₆]⁺ where M=a        trivalent metal ion;    -   A trimetallic carboxylate complex (e.g. [M₂M′O(O₂CR)₆] where M=a        trivalent metal ion, M′=a divalent metal ion;    -   A hexametallic carboxylate complex (e.g. [M′₄M₂O₂(O₂CR)₁₂] where        M=a trivalent metal ion, M′ a divalent metal ion);    -   a dodecametallic complex such as [M₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆]        where chp=6-chloro-2-pyridonate, where M=Ni or Co.

In a particular embodiment, PMC is selected from [M¹ _(x)M²_(y)(monoLIG¹)_(m1)(O₂CR_(B1))₁₆] or [Cr₇NiF₈(O₂CR_(B1))₁₆]; and LINK isdefined by Q-[CORE]-[W]_(w); wherein [CORE] comprises a single coregroup to which the Q group and the or each of the W group(s) arecommonly attached; each Q and/or W group is independently selected fromelectron pair-donating co-ordinating moieties, such as those containingone or more heteroatoms, such as nitrogen, oxygen, and/or sulphur. In aparticular embodiment, [CORE] is a macrocycle and each Q and W group isas defined herein.

In a particular embodiment, the anti-scattering compound is as definedin the specific embodiments above, wherein the primary metal complex isdefined by or comprise units defined by the Formula IIc:

[Cr₇NiF₈(O₂CR_(B1))₁₆];

wherein R_(B1) is as defined herein, though most suitably R_(B1) ist-butyl; andLINK is a single molecule, ion, or complex comprising two or moreco-ordinating moieties, each co-ordinating moiety being capable ofaccepting or donating one or more lone pairs of electrons, though mostsuitably LINK is:

In a particular embodiment, PMC is selected from[M8-yM2yF3(O2CRB1)15(Gluc-NH—RO1)], [Cr7NiF3(O2CRB1)15(Gluc-NH—RO1)];and LINK is defined by Q-[CORE]-[W]w; wherein [CORE] comprises one ormore core group to which the Q group and the or each of the W group(s)are commonly attached; each Q and/or W group is independently selectedfrom electron pair-donating co-ordinating moieties, such as thosecontaining one or more heteroatoms, such as nitrogen, oxygen, and/orsulphur. In a particular embodiment, [CORE] is a macrocycle and each Qand W group is as defined herein.

In a particular embodiment, the anti-scattering compound is as definedin the specific embodiments above, wherein the primary metal complex isdefined by or comprise units defined by the Formula IIIa:

[Cr₇NiF₃(O₂CR_(B1))₁₅(Gluc-NH—R_(O1))]

wherein R_(B1), and Gluc-NH—R_(O1) are as defined herein, though mostsuitably R_(B1) is t-butyl and R_(O1) is methyl; andLINK is selected from the group including:

-   -   a terminal ligand, e.g. H₂O, pyridine or a substituted pyridine,        where n=1.    -   A bridging di-imine, e.g. 4,4′-bipyridyl, 1,2-dipyridylethene,        1,4-dipyridyltetrazine    -   another poly-pyridyl ligand, e.g. including pyridyls substituted        around macrocycles such as porphyrins or phthalocyanines;        though most suitably LINK is:

Suitably in such embodiments, the antiscattering compound has a densityless than or equal to 1.2 g/cm³, a molecular weight greater than orequal to 10,000, and also suitably a solubility in hexane (at SATP) ofat least 10 mg/g.

In a particular embodiment, an eBeam resist coating (formed from theeBeam resist composition) of the invention consists essentially of theantiscattering compound. However, the skilled person may judiciouslyadjust the balance of components within the eBeam resist compositiondepending on the required performance.

In preferred embodiments, an eBeam resist coating (formed from the eBeamresist composition) of the invention may have any one or more of theproperties (e.g. mean free path, scattering cross-section, density,molecular weight) defined herein in relation to the antiscatteringcompound itself. As such, in some embodiments where an eBeam resistcoating (and its corresponding eBeam resist composition) comprises oneor more components in addition to the antiscattering compound, thepresence of said one or more components does not compromise theseproperties.

Electron-Beam Lithography Using eBeam Resist Compositions of theInvention

The present invention provides a method of performing electron-beamlithography, the method comprising:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate;    -   ii) exposing part(s) of the (eBeam) resist coating to (electron        beam) radiation to provide an exposed (eBeam) resist coating;    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) optionally modifying the substrate, substrate surface, or        part(s) thereof, underlying the (eBeam) resist pattern layer;    -   v) optionally removing the (eBeam) resist pattern layer to        provide a modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (optionally with an alternative resist coating, such        as a photoresist, instead of the eBeam resist coating; and        optionally using alternative radiation during exposure, such as        visible or ultraviolet light, instead of electron beam        radiation) upon the modified substrate.

Step (i) of the method is optionally preceded by performing steps (i) to(vi) (i.e. pre-steps (i)-(vi)), optionally repeated one or more times,using either an eBeam resist coating or an alternative resist coatingand using either electron beam radiation or alternative radiation duringexposure;

The eBeam resist coating suitably comprises or consists essentially ofan optionally dried and/or cured eBeam resist composition; wherein theeBeam resist composition comprises an anti-scattering compound.

The invention further provides an imaged substrate obtainable by,obtained by, or directly obtained by this method.

Such methods may be used for imaging, for preparing patternedsubstrates, for selectively modifying a surface of a substrate, and formanufacturing a multi-layered substrate (e.g. integrated circuit),suitably as defined herein.

In a particular embodiment, the above method is used in the productionof an integrated circuit (which is an example of a multi-layeredsubstrate) or plurality thereof (e.g. on a wafer). The skilled person iswell aware of standard manufacturing processes used in the production ofintegrated circuits. The method of the invention may be used to produceone or more layers of an integrated circuit, and in some embodiments maybe used to produce all layers. However, since high resolution may onlybe required for one or some resolution-critical layers (e.g. ifresolution is not important for every layer), alternative lithographicmethods may be involved in the production of other layers (e.g.photolithography). In this manner, electron beam lithography maycomplement other forms of lithography (e.g. photolithography) in thefabrication of integrated circuits.

Substrate

The substrate upon which electron-beam lithography is performed may beany suitable substrate.

The substrate is suitably a single solid body, or a portion thereof. Thesubstrate is suitably in the form of a (substantially rigid) plate,wafer, or sheet, most suitably a wafer.

Since, in accordance with the methods of the invention, certainprocessing steps may be “repeated” (including steps which refer to a“substrate”), the “substrate” may refer to the initial “input substrate”(i.e. before any method steps of the invention are performed) or a“modified substrate” (following certain method steps). As such, inprinciple the “substrate” may be any substrate (including partiallyfabricated products or integrated circuits) which is suitable forprocessing via electron-beam lithography.

The substrate (whether the input substrate or modified substrate) issuitably either part of a pre-formed resist-coated substrate or is asubstrate to which a resist coating is applied (e.g. in step i) of manyof the methods disclosed herein). As such, the substrate may be defined(whether in terms of its nature, parameters, material form, etc.)without reference to the resist coating itself. The substrate ormodified substrate may be planarized prior to coating with a resistcoating.

In some embodiments, the substrate (or part thereof) to which themethod(s) of the invention is applied is incorporated into a final(printed) product (e.g. integrated circuit), though this may itself beincorporated into products (e.g. circuit boards and/or electronicdevices). In other words, the “imaged substrate” may be or become aconsumable product or may otherwise be or become incorporated into aconsumable product. Such consumable products include an integratedcircuit, integrated circuit die or wafer, integrated circuit package, acircuit board, or an electronic device or system.

In some embodiments, however, the substrate (or part thereof) to whichthe method(s) of the invention is applied is not incorporated into afinal (printed) product (e.g. integrated circuit) but is ratherincorporated into a tool, for example a lithographic mask (whetherpositive or negative) such as a photomask for use in photolithography,used to produce such a final (printed) product. In other words, the“imaged substrate” may be a tool for producing a consumable product. Assuch, the advantages of the invention (e.g. high resolution) may beimparted to a lithographic tool (e.g. a lithographic mask withhigh-resolution detail), which may thereafter be imparted to a final(printed) product made using said tool. As such, ultra high-resolutionelectron beam lithography (as per the invention) may be used to producea corresponding ultra high-resolution lithographic mask (e.g. photomask)which may in turn be used in ultra high-resolution lithography, such asphotolithography, to produce ultra high-resolution integrated circuits(or one or more ultra high-resolution layers thereof). As such, theinvention provides a method of manufacturing a lithographic mask and alithographic mask (e.g. photomask) as defined herein; as well as a useof such a lithographic mask in the production of an integrated circuit,integrated circuit die or wafer, integrated circuit package, a circuitboard, or an electronic device or system).

The substrate suitably comprises or consists essentially of a substratebase material.

The substrate base material may comprise or consist essentially of anysuitable material for use in the method(s) of the invention. Thesubstrate base material (and suitably also the substrate base layer as awhole) is suitably a single substance (element or compound) or a singlecomposite material (mixture of two or more elements and/or compounds).However the substrate base material may be a multi-layered compositematerial.

Where the substrate (or part thereof) is not incorporated into a final(printed) product (e.g. integrated circuit) but is rather incorporatedinto a tool (e.g. lithographic mask), suitably the substrate basematerial is a material appropriate for the tool in question. Suitably,the substrate base material is a lithographic plate (potentiallycomprising one or more layers of one or more materials). Where the toolis a lithographic mask (e.g. a photomask), the substrate base materialmay be (substantially) transparent or (substantially) non-transparent tothe relevant radiation (e.g. UV or visible light, if a photomask),depending on the ultimate nature of the mask. For instance, a substratebase material that is (substantially) transparent to the relevantradiation may be used where a lithographic mask is formed throughgenerating opaque regions on the substrate base material during the maskmanufacturing process (e.g. non-removed resist coating may provideopaque regions, or opaque regions may be generated by judicious surfacemodifications). Alternatively, a substrate base material that is(substantially) opaque or non-transparent to the relevant radiation maybe used where a lithographic mask is formed through generatingtransparent regions on the substrate base material during the maskmanufacturing process (e.g. where the process involves surfacemodifications which remove portions of substrate base material—e.g. viaetching). In other embodiments, the substrate base material may be alaminated composite, comprising at least one layer of material which is(substantially) transparent to the relevant radiation (e.g. glass,transparent plastics) and at least one layer of material which is(substantially) opaque to the relevant radiation—under suchcircumstances, the process of manufacturing a lithographic mask mayinvolve removal or regions of opaque material to leave transparentportions.

Lithographic masks, such as photomasks may comprise a layer oftransparent fused silica covered by a pattern defined with a chromemetal-absorbing film, the pattern having been generated in accordancewith methods of the invention to thereby afford high resolutionpatterns. Such masks may then be used in lithographical methods of theinvention to produce high-resolution products, such as integratedcircuits.

Where the substrate (or part thereof) is to be incorporated into a final(printed) product, suitably the substrate base material is a materialappropriate for the product in question. In a particular embodiment, thebase substrate is an electronic component substrate. A suitableelectronic component substrate may include a substrate comprising or be(substantially) made of silicon (e.g. a silicon wafer), copper,chromium, iron, aluminium, or glass. The base substrate may itselfcomprise a surface coating, e.g. as an undercoat to the resist coatingto be applied thereto. In a particular embodiment the base substrate isa silicon substrate. The substrate base material may comprise or consistessentially of a semiconductor material, most suitably silicon, mostsuitably a single monolithic silicon crystal. Most suitably, thesubstrate base layer is a silicon wafer. Suitably, where the resistcoatings and compositions of the invention are used in the fabricationof integrated circuits, the input substrate may be apartially-fabricated integrated circuit, wherein some layers of theintegrated circuit have already been formed (optionally with or withoutusing the resist coating or composition of the invention—other layersmay be formed using traditional IC fabrication techniques, such asstandard photolithography). Furthermore, after the eBeam resist coatingsof the invention have been used (and suitably removed) during thefabrication of part of an integrated circuit, further layers of theintegrated circuit may be formed (optionally with or without using theeBeam resist coating or composition of the invention—again other layersmay be formed using traditional IC fabrication techniques, such asstandard photolithography)

The substrate may consist essentially of a substrate base material (e.g.where the input substrate is yet to be modified, for example, viasurface oxidation, lithography and/or other substrate modificationstep(s)).

However, alternatively the substrate (which may include the inputsubstrate) suitably comprises a substrate base material (suitablyconsisting essentially of substrate base material) that has been subjectto modification (e.g. a modified substrate). Such a modified substratemay include a substrate base material that has been modified by apre-processing or pre-coating step (e.g. thermal oxidation of a surface,e.g. to produce a silicon oxide insulation layer prior to coating with aresist coating) before being subjected to the method(s) of theinvention; otherwise modified prior to being subjected to the method(s)of the invention (e.g. a partially formed integrated circuit formedusing alternative technologies, e.g. using photolithography); or elsemodified during or after the substrate has been subjected to themethod(s) (or some of the step(s) thereof) of the invention. Eachfurther substrate layer suitably comprises or consists essentially of afurther substrate material, which may be the same as or different fromthe substrate base material. In a particular embodiment, one nor more ofthe further substrate layers comprises or consists essentially of thesubstrate base material, albeit not necessarily part of the substratebase layer.

Suitably the substrate base layer is disposed towards (or at) the baseof the substrate, suitably relative to an exposure surface thereof (i.e.the surface whose resist coating is to be exposed to radiation—this maybe considered a top of the substrate, regardless of the ultimateorientation of the resist-coated substrate during processing).

Suitably the method(s) of the invention involve generating additionallayer(s) (including partial layer(s)) upon the substrate base layer andoptionally thereafter upon each other; incorporating additional layer(s)within either the substrate base layer or any further substrate layer(s)(e.g. via doping); and/or removing part(s) of the substrate base layerand/or part(s) of further substrate layer(s) (e.g. via etching).Suitably the method(s) of the invention produce a multi-layeredsubstrate comprising a substrate base material towards (or at) thebottom thereof. The substrate base layer is suitably the foundation uponwhich the other layers are built.

In preferred embodiments, the input substrate comprises a substrate baselayer underlying a layer of oxidised (preferably thermally oxidised)substrate base material. In a particular embodiment, the input substratecomprises a wafer of silicon (suitably a single crystal of silicon)underlying a silicon oxide (or silicon dioxide) layer.

As will be appreciated by the skilled person, where a lithographic mask(e.g. photomask) formed by the method(s) of the invention (i.e. usingeBeam and the relevant eBeam resist coating of the invention) is used insubsequent lithography (e.g. to form an alternative imaged substrate,multi-layered substrate, integrated circuit, etc.), the same substratebase material (e.g. silicon wafer) may be used. Moreover the samelithographic methods defined herein may be used, though alternativeresist coating(s), lithographic methods (e.g. exposure and developmentmethods) may be used with the lithographic mask instead of or inaddition to (e.g. in repeated steps) the eBeam resist coating(s) andeBeam-specific method steps of the invention.

Although the methods of the invention are especially applicable for theproduction of silicon-based integrated circuits, and products derivedtherefrom, the present invention will be equally applicable to futurematerials used in the construction of electronic components—for instancegraphene based materials.

EBeam Resist-Coated Material and its Formation

The present invention provides an eBeam resist-coated material, and amethod of forming an eBeam resist-coated material, as defined herein. AneBeam resist-coated material or substrate is a “substrate” as definedherein with an eBeam resist coating on a surface (or part of a surface)thereof.

The eBeam resist-coated material suitably involves coating the inputsubstrate with an eBeam resist composition as defined herein, andoptionally thereafter curing and/or drying the coating, to form acoating of eBeam resist composition upon the substrate.

Coating the input substrate, which suitably involves applying the resistcomposition (whether an eBeam resist or alternative resist) to asurface(s) of the input substrate, may be performed by any number ofmethods well known to the person skilled in the art. Applying a resistcoating to a substrate (be it a single body of substrate base material,a multilayered substrate, an input substrate, or a modified substrate)suitably involves applying a resist composition (suitably as definedherein, though alternative resist compositions outside the scope of theinvention may be used in addition, so long as the resist composition ofthe invention is used at least once in the method(s) of the invention)to a surface (or part of a surface) thereof and optionally thereaftercuring and/or drying the applied resist composition to form the resistcoating. The resist composition may be applied in any suitable mannerthough most suitably the resist composition is applied via dipping,spraying, brushing, roller coating, and/or spin coating. Most preferablythe resist composition is applied to the substrate via spin coating,which is especially suitable during the fabrication of integratedcircuits. In a particular embodiment, the eBeam resist composition isapplied to the base substrate or input substrate via spin-coating (e.g.using a spinner), suitably to thereby form a resist spin-coated inputsubstrate. Most suitably the applied resist composition is cured and/ordried (suitably through baking). The resist coating suitably has a(substantially) uniform thickness. The skilled person is well versed inhow to apply a resist coating to a substrate prior to lithography.

Where a substrate is said to comprise or be coated by a coating, such asa resist coating, said coating suitably covers a surface (or partthereof) of said substrate.

After coating the base substrate or input substrate with the resistcomposition, the coating is preferably cured and/or dried. Suitably, thecoating is dried at a temperature and pressure and for a time suitableto form a resist film upon the base substrate or input substrate. Thetemperature (and pressure, especially where reduced pressure is used)may be chosen for compatibility with the particular solvent of theresist composition (e.g. to boil off the solvent). In a particularembodiment, the coating (or coated-base substrate or coated-inputsubstrate) is baked at atmospheric pressure (approximately 1 Bar) and atemperature between 60 and 200° C. (more suitably between 80 and 180°C.) for between 30 seconds and 5 minutes (suitably between 90 and 150seconds, suitably around 120 seconds). Suitably such curing/drying mayremove some, most, or all solvent(s) present in the resist composition.Where the anti-scattering compound(s) are associated with a solvate,suitably some, most, or all of said solvate is removed by said curingand/or drying.

The average thickness of the coating is suitably 10-500 nm, suitably50-200 nm. The maximum thickness of the coating is suitably 1000 nm,suitably 500 nm. The minimum thickness of the coating is suitably 5 nm,suitably 20 nm. The technology of the present invention allowseffective, high quality patterning of extremely thin resist coatings.

The resist coatings of the invention provide good adhesion to basesubstrates and input substrates, especially those suitable forelectronic components.

Though the above description of the application of a resist coatingsuitably pertains to eBeam resist coatings, any of the descriptions mayequally apply (where compatible) to the application of alternativeresist coatings, such as photoresists, though the skilled person will bewell able to adapt solvents and coating techniques to suit the resistcoating in question.

Exposure and Electron Beam Radiation

Exposing part(s) of the eBeam resist coating to electron beam radiationprovides an exposed eBeam resist coating. In pre-steps and/or repeatsteps, where an alternative resist coating and optionally alternativeradiation is used, exposing part(s) of the relevant resist coating toradiation provides an exposed resist coating.

Exposing part(s) of the coating of the eBeam resist-coated material toradiation suitably involves selectively exposing said part(s), whilstother part(s) are selectively non-exposed. As such, the method suitablyexcludes exposing all of the coating to radiation.

Selective exposure of part(s) of the coating may involve directirradiation of the relevant part(s) with a focused or targeted beam(e.g. such as an electron beam or laser beam, e.g. a UV-laser beam,preferred when using eBeam resists) or blanket flood exposure (i.e.unfocussed/untargeted) exposure of the coating through a mask (e.g.photomask, preferred when using photoresists) comprising pre-determinedapertures corresponding with the position of the exposed part(s) of thecoating. The particular exposure technique used may depend on theparticular radiation being employed.

Suitably the exposed part(s) of the coating undergo a transformation,suitably a chemical transformation, suitably which changes thesolubility properties thereof (suitably in relation to a pre-determineddeveloping medium, for example, one of the developing media describedherein), suitably whether before or after an optional post-exposurebake, suitably even before any such post-exposure bake.

Suitably, parts of the coating which are “radiation-exposed” havedifferent solubility properties to parts of the coating which are not“radiation-exposed”. This solubility differential suitably allows fordevelopment and selective removal of either the “radiation-exposed” or“non-radiation-exposed” parts of the coating (depending on whether theresist is positive or negative tone resist).

In general, the resist material(s) (which may include an antiscatteringcompound and/or a base polymeric component) in the exposed part(s) ofthe coating is, at least partially, fragmented (i.e. through chemicalbond-breakages, suitably via chain scission methods, suitably caused byirradiation), suitably into shorter polymeric or monomeric fragments.Such fragmentation is suitably caused by primary radiation (e.g. primaryelectrons of an eBeam) and/or secondary electrons (optionally producedby a secondary electron generator in response to primary radiation).Suitably, such shorter fragments have a higher solubility in thedeveloping medium than the original base polymeric component.

Where the resist composition or resist coating is positive tone (i.e. apositive resist), suitably the exposed part(s) of the coating becomemore soluble (suitably in relation to a pre-determined developingmedium, for example, one of the developing media described herein). Assuch, the net effect of irradiation (and optionally a post-exposurebake) is to increase the solubility of exposed part(s) of the resistcoating. As such, suitably the exposed part(s) are intended to beremoved after subsequent developing. Suitably, the increase solubilityof the resist coating is the result of the aforementioned break down ofthe base polymeric component.

Where the resist composition or resist coating is negative tone (i.e. anegative resist), suitably the exposed part(s) of the coating becomeless soluble (suitably in relation to a pre-determined developingmedium, for example, one of the developing media described herein). Assuch, the net effect of irradiation (and optionally a post-exposurebake) is to reduce the solubility of exposed part(s) of the resistcoating. As such, suitably the exposed part(s) are intended to remainafter subsequent developing. Since the aforementioned break down of thebase polymeric component generally leads to elevated solubility,negative tone resist compositions suitably additionally comprise anegative resist agent, such as a cross linking agent. Such across-linking agent may suitably cross-link the base polymericcomponent, or any polymeric or monomeric fragments thereof (see above),during irradiation and/or during any optional post-exposure bake, tothereby provide a cross-linked polymeric component that is less solublethan the original base polymeric component. It will be readilyrecognized, by those skilled in the art, that radiation above a certainenergy and/or intensity threshold may lead to negative resists becomingpositive resist, merely because the negative resist agent (e.g.cross-linking agent) may itself be broken down and/or destroyed, therebypreventing it from performing its intended function. As such, a negativeresist may only act as a negative resist within certain limits, whichare straightforward for the skilled person to determine.

Exposure of the coating may lead directly to a developable substrate(i.e. a substrate which can undergo development to produce a patternedsubstrate). However, additional subsequent processing steps may beemployed. Suitably, radiation exposure of the coating may be followed bya post-exposure bake. The post-exposure bake may comprise baking at atemperature and pressure and for a time suitable to form a developablesubstrate. The temperature (and pressure, especially where reducedpressure is used) may be chosen for compatibility with the particularsolvent of the resist composition (e.g. to boil off the solvent). In aparticular embodiment, the exposed coating (or exposed coated-basesubstrate or exposed coated-input substrate) is baked at atmosphericpressure (approximately 1 Bar) and a temperature between 60 and 200° C.(more suitably between 80 and 180° C.) for between 30 seconds and 5minutes (suitably between 90 and 150 seconds, suitably around 120seconds).

Any radiation suitable for use with resist compositions may be used.Suitably resist compositions are formulated for exposure with particularradiation, so the radiation may be selected base on the resistcomposition question. Suitably the radiation in question is eitherelectromagnetic radiation (especially ultraviolet) or an electron beam.Obviously, the eBeam resist compositions and coatings of the inventionare designed to be exposed by electron beam radiation. Alternativeresist compositions and coatings are most suitably designed for exposureby light, suitably UV or visible light (i.e. as in photolithography),most suitably via a photomask.

Suitably the radiation is electron beam radiation (i.e. provided by anelectron beam). Suitably the electron beam radiation is a focused,targeted beam, thereby allowing direct irradiation of the relevantpart(s) of the coating (i.e. without any masking). As such, exposure ofthe coating using an electron beam may involve (effectively) writingupon the coating with the beam. The energy (or acceleration voltage),current, and write speed of the electron beam may be judiciouslyselected by the skilled person, depending on the circumstances. However,to expose the eBeam resist coatings of the invention, the electron beamradiation (i.e. primary electrons) suitably may have an initial energy(or acceleration voltage) between 10 and 300 keV, suitably between 30and 200 keV, suitably between 50 and 150 keV, most suitably between 90and 110 keV. The electron beam suitably has a current between 25 and 300μA/beam (pA=pico amperes), suitably between 50 and 270 pA/beam, mostsuitably between 200 and 250 pA/beam. Where the electron beam isemployed as a focused, targeted beam (i.e. for writing), the electronbeam suitably has a write speed (or exposure dose) below 30 μC/cm²(uC=unit of electronic charge, uC/cm²=electronic charge per unit area),suitably below 20 μC/cm², more suitably below 10 μC/cm², most suitablybelow 5 μC/cm². The write speed may be as low as 0.5 μC/cm², but issuitably greater than or equal to 0.5 μC/cm², suitably greater than orequal to 1 μC/cm². In a particular embodiment, the radiation is anelectron beam having an energy between 15 and 60 keV, a current between25 and 300 pA/beam, and a write speed below 20 μC/cm². The presentinvention allows the use of low energy electron beams, therebyminimizing damage to components of the resist composition (e.g. tocross-linking agents), which may compromise the function of the resist.An electron beam can be generated by methods well known to those skilledin the art.

In an embodiment, where alternative resist coatings are used alongsidenon-eBeam radiation (e.g. ultraviolet radiation), suitably saidradiation has a wavelength between 10 and 400 nm. Where ultravioletradiation is used for exposure, the resist composition (and hence theresist coating) will suitably comprise additional ingredients (e.g. aphotoacid and/or photocatalyst) which facilitate the coatingtransformation process upon exposure to ultraviolet radiation. Theultraviolet radiation may give rise to secondary electrons duringexposure (in much the same manner as with electron beam radiation,albeit the secondary electrons may be generated more indirectly),especially in the presence of a secondary electron generator as definedherein. The ultraviolet radiation can be generated by methods well knownto those skilled in the art. The ultraviolet radiation may beextreme-ultraviolet (EUV), suitably having a wavelength between 10 and124 nm, suitably between 10 and 20 nm, suitably between 11 and 15 nm(most suitably about 13.4 nm). Alternatively, the ultraviolet radiationmay suitably have a wavelength between 150 and 240 nm, suitably between180 and 210 nm, suitably between 190 and 200 nm, suitably about 193 nm.

Suitably, where an antiscattering compound, as defined herein, ispresent within a resist composition (and resist coating), exposure ofthe resist composition or coating thereof will be more controlled thanin the absence of said antiscattering compound. The antiscatteringcompound is thought to focus and direct the radiation (and optionallyalso secondary electrons, where they are duly generated) to the desiredexposure sites, to suitably thereby minimize any undesired exposure. Inother words, the antiscattering compound may prevent radiation (and/orsecondary electron) spillage, and thereby confine the transformationaleffects of the radiation (and/or secondary electrons) to ensure higherresolution exposure. Moreover, the antiscattering compound can preventor reduce over-exposure of certain vulnerable components within theresist, e.g. a cross-linking agent (where negative tone resists aredesired), which may otherwise compromise subsequent developing of theexposed resist.

Developing the Resist Coating and the Developing Medium

The present invention provides a patterned substrate, and a method forits preparation (e.g. developing an exposed eBeam resist-coatedmaterial), as defined herein. Suitably, “development” forms grooveswithin the resist coating to thereby form a pattern layer.

The step of developing the exposed eBeam resist coating generates aneBeam resist pattern layer comprising developer-insoluble coatingportions of the eBeam resist coating (i.e. ridges) and an array ofgrooves extending through the eBeam resist pattern layer. In certainembodiments, a surface of the substrate underlying the resist patternlayer is exposed in/by the grooves, though is suitably masked by theridges.

Developing the exposed resist-coated material is suitably performed witha developing medium. As such, the exposed resist-coated material, or atleast the exposed coating thereof, is suitably contacted with (e.g.washed with and/or immersed within) a developing medium (which issuitably liquid) in a manner sufficient to remove (suitably throughdissolving) either the exposed part(s) (for positive resists) ornon-exposed part(s) (for negative resists) of the coating of the resistcomposition. For eBeam resist coatings of the invention, the developingmedium suitably removes non-exposed part(s).

As aforementioned, exposure of the resist-coated material generallycauses exposed part(s) of the coating to have a different solubility(suitably in relation to a pre-determined developing medium) tonon-exposed part(s) of the coating. This solubility differential betweenthe exposed and non-exposed part(s) of the coating is instrumental infacilitating subsequent development of the exposed coated-resistmaterial. As such, either the exposed or non-exposed part(s) of thecoating may be selectively removed (preferably dissolved) to transformthe coating into a pattern layer comprising an array of groovesextending through the pattern layer (i.e. through what was the originalcoating). The grooves of the pattern layer then correspond with thepart(s) of the coating that have been removed, whereas theridge/protrusion (i.e. non-groove) part(s) of the pattern layercorrespond with the part(s) of the coating that remain. The patternlayer (suitably the non-groove part(s) thereof) therefore suitablycomprises ridges or protrusions (i.e. between the grooves) which areeither exposed part(s) (for positive resists) or non-exposed part(s)(for negative resists) of a coating of the resist composition.

The specific developing conditions may be tuned, for instance, tooptimise the quality of the resulting patterned substrate, or optimisethe developing process (whether in the interests of cost, speed, orultimate product quality). Developing times (for instance, the time ifimmersion of the exposed coating) may, for example, be optimised tomaximise removal of the part(s) of the coating intended for removal andto minimise removal or damage of part(s) of the coating intended toremain. Likewise, the developing medium may be tuned to optimise eitheror both the developing process or the resulting product.

Suitably, after developing, the method of preparing a patternedsubstrate comprises rinsing the pattern layer, suitably with a rinsemedium, which suitably comprises an organic solvent.

Suitably, after developing, and optionally after rising, the methodfurther comprises drying (or baking) the patterned substrate.

The developing medium itself may be any suitable developing medium knownin the art. Suitably the developing medium complements the resistcomposition (or coating thereof). Most suitably the developing mediumcomplements the solubility properties of the resist composition and itspost-exposed counterpart, suitably to optimize contrast (i.e. thedifferential solubility and/or solubilization rates) between exposed andunexposed parts of the resist coating. Where the resistcomposition/coating is an eBeam resist composition/coating of theinvention, suitably the developing medium dissolves unexposedantiscattering compound.

Where the resist composition (or coating thereof) is a negative resist,the developing medium suitably comprises a solvent within which theantiscattering compound and/or base polymeric component is(substantially) soluble, or is at least more soluble than a post-exposedcounterpart of the antiscattering compound and/or base polymericcomponent. Where the resist composition (or coating thereof) is apositive resist, the developing medium suitably comprises a solventwithin which the antiscattering compound and/or base polymeric componentis (substantially) insoluble, or at least less soluble than apost-exposed counterpart of the antiscattering compound and/or basepolymeric component.

The developing medium may or may not dissolve all components of theexposed or non-exposed (depending on whether positive or negativeresist) resist composition (or a coating thereof) intended for removalby development, but any insoluble (or less soluble) components may stillbe removed in slurry, suspension or dispersion following dissolution (orpartial dissolution) of the base polymeric component or post-exposedcounterpart thereof with which said insoluble components are mixed.

The developing medium for the eBeam resist coatings of the inventionsuitably comprise or consist of an organic solvent, suitably a non-polarorganic solvent, suitably which is an organic compound. The organicsolvent is suitably selected from one or more hydrocarbon solvents,suitably one or more (4-12C)hydrocarbon solvents. For example, theorganic solvent may be selected from one or more of pentane, hexane,octane, decane, 2, 2, 4-trimethylpentane, 2, 2, 3-trimethylpentane,perflurohexane and perfluronpetane and aromatic hydrocarbon solvents,such as toluene, ethylmethpropylbenzene, dimethylbenzene,ethyldimethylbenzene and dipropylbenzene). In a particular embodiment,the developing medium for eBeam resist coatings of the invention ishexane.

The pattern layer may be considered to comprise an array of groovesextending through the pattern layer (i.e. a groove pattern) and an arrayof ridges/protrusions (i.e. the non-groove part(s) of the patternlayer). The ridges suitably correspond with developer-insoluble coatingportions whereas the grooves suitably correspond with developer-solublecoating portions (i.e. which are removed upon developing).

The present invention allows extremely high resolutions to be achieved.The resolution of the pattern layer (particularly the groove and/orridge pattern) generated using the eBeam resist coating of the inventionis suitably less than 50 nm, suitably less than 20 nm, more suitablyless than 10 nm, and suitably less than 7 nm. Typically the resolutionis at least 1, suitably at least 2 nm, suitably at least 5 nm. Suchresolutions may even be achieved with high energy radiation exposure,for instance, with electron beams of an energy of 10 keV or higher.

Moreover, one of the particular advantages of the eBeam resist coatingsof the invention is that the grooves (or trenches) produced followingdevelopment of an exposed eBeam-resist-coated substrate have(substantially) vertical walls, as opposed to sloping walls. Suitablythe walls of the grooves are substantially perpendicular (e.g.90°+/−20°, suitably +/−100, suitably +/−50, most suitably +/−10) to theunderlying substrate surface. This significantly improves theeffectiveness and resolution of subsequent surface modification steps.For instance, the profile of the walls of any trenches formed by etchingare substantially perpendicular (e.g. 90°+/−20°, suitably +/−100,suitably +/−50, most suitably +/−10) to the underlying substrate surface(i.e. the bottom of the trenches). Such clean patterning and subsequentsurface modification is achievable due to the lack of scattering eventsand secondary electrons generated by the anti-scattering compoundfollowing collisions with primary electrons. Thus the presence of suchclean patterning and/or surface modifications in a final integratedcircuit is indicative of the present invention having been employed.

The aspect ratio of the grooves (i.e. width/height ratio) may besuitably greater than or equal to 1:1, suitably greater than or equal to5:1, suitably greater than or equal to 10:1, and impressively an aspectratio of greater than or equal to 15:1 or even greater than or equal to20:1 may be achieved. The technology underlying the present inventionallows extremely high aspect ratios to be achieved, especially where ananti-scattering compound is employed.

Further Processing of Patterned/Developed Substrate

After developing the exposed resist coating, the surface of thesubstrate underlying the patent layer may be selectively modified in anyone or more of a number of ways. Since the step of selectively modifyingthe substrate, substrate surface, or part(s) thereof, may be repeatedindefinitely (before or after removing any residual resist patternlayer, and optionally after further lithography stages), one or moresuccessive selective substrate/surface modification steps may ensue,which may optionally be selected from any of those detailed herein, or acombination thereof.

Suitably the part(s) of the substrate/surface modified during suchselective modification are the part(s) exposed by or underlying thegrooves in the pattern layer (i.e. the underlying surface to be modifiedmay be exposed/visible or have only a relatively thin layer of resistremaining thereupon).

Selectively modifying the substrate/surface may involve removing part(s)of the substrate/substrate surface, adding or depositing a material to(or upon) the substrate/substrate surface, and/or changing part(s) ofthe substrate/substrate surface.

Modifying the substrate/surface may by removing part(s) of thesubstrate/substrate surface may, for instance, involve etching thesubstrate/surface. In the context of integrated circuit fabrication,typically such etching is performed to remove an insulating material(e.g. silicon oxide/dioxide layer, e.g. suitably which protectsunderlying conductive material), suitably to thereby uncover anunderlying conductive material (e.g. silicon). Alternatively oradditionally, etching may involve etching a conductive material (e.g.silicon)—e.g. capacitors may be produced via trenches etched deep into asilicon surface.

In the context of manufacturing a lithographic mask (e.g. a photomask),such etching may remove an opaque material or layer to reveal anunderlying transparent material through which radiation may pass (e.g.during lithographic exposure through said resulting lithographic mask).

Etching would suitably selectively etch the part(s) of thesubstrate/surface underlying the groove(s) of the pattern layer ratherthan the part(s) of the substrate/surface underlying the ridges (whichare essentially protected).

Modifying the substrate/surface by changing part(s) of thesubstrate/substrate surface may, for instance, involve altering thetransparency properties of the substrate/surface (e.g. in producing alithographic mask) or altering the electrical properties of thesubstrate/surface (or the relevant part(s) thereof) (e.g. when producingan integrated circuit). Altering the electrical properties of thesubstrate/surface is particularly applicable where the underlyingsubstrate/surface being modified (e.g. that exposed by the grooves) is asemicoinductor (e.g. silicon). Alteration of the substrate/surface(s)electrical properties may involve “doping” of the relevant part(s) ofthe substrate/surface. Doping is a well known phenomenon in the field ofsemiconductor technology, and facilitates the creation of electroniccomponents within an integrated circuit (e.g. diodes, logic gates,transistors, etc.). Such doping can be performed using techniques wellknown in the art, such as diffusion (e.g. where a dopant is diffusedinto the substrate so that it becomes embedded therein), ionimplantation (e.g. where an ion beam implants ions into the substrate).

Doping can, however, be achieved through pre-deposition, such as byepitaxial growth of a doped deposit (e.g. epitaxial growth of an Si—Gelayer).

Modifying the substrate/surface by changing part(s) of thesubstrate/substrate surface may alternatively or additionally involveforming an insulation layer (or isolation layer), or gate, suitably bytransforming part(s) of the substrate/surface—e.g. through thermaloxidation (e.g. thermal oxidation of a conductor, such as silicon,produces the insulator silicon dioxide).

Modifying the substrate/surface by adding or depositing a material to(or upon) the substrate/substrate surface may, for instance, involvedeposition of an insulating material, for instance, to isolate anelectronic component or conductive element. Alternatively it may involvedeposition of a conductive material (e.g. metal plating etc.).

Any, some, or all of the aforementioned surface modification steps maybe deployed (suitably in succession, though optionally interspersed withlithographic steps—e.g. re-coating, re-exposure, re-development) to forma multi-layered substrate, such as an integrated circuit (e.g. die orwafer).

Suitably, at a certain stage (e.g. following one or more surfacemodifications), one or more resist pattern layers (which may or may notbe an eBeam resist pattern layer) are removed. A variety of techniquesknown in the art may be deployed for such removal (e.g. chemicalremoval, physical removal, thermal treatment, radiative removal orplasma ashing, or a combination.), though plasma ashing may be employedin the context of integrated circuit fabrication. Alternatively, theresidual resist pattern layer(s) may be removed with a solvent (e.g.through dissolution) or via a selective etching process.

In some embodiments, once a resist pattern layer is removed, the entiremodified surface may be treated/modified in toto.

Step (vi) allows for repetition of a surface modification step, so thatsuccessive surface modification steps may be performed (before and/orafter pattern layer removal). In addition, step (vi) allows alllithography steps (steps i)-iii))), further surface modification steps(step iv)), and optional pattern layer removal (step v)) steps, to berepeated any number of times. So long as the method comprises at leastone step involving an eBeam resist composition/coating of the inventionor at least one step involving a tool (e.g. lithographic mask) of theinvention, any or all of the repeated steps may employ an alternativeresist coating and where appropriate alternative radiation (duringexposure) instead of the eBeam resist coatings of the invention andelectron beam radiation (during exposure). Alternatively, any or all ofthe repeated steps may employ the eBeam resist coating of the inventionand electron beam radiation. It should therefore be evident that therepeating steps are not limited, and permit a multiplicity of methodsteps outside the scope of the invention, suitably in the production ofintegrated circuits and the like.

In the context of fabricating an integrated circuit, selectivelymodifying the substrate/surface (or part(s) thereof) may involvefront-end-of-line (FEOL) processing (e.g. formation of electroniccomponents, such as transistors, directly in the substrate, i.e.silicon). In fact, steps (i) to (vi) may collectively constitutefront-end-of-line (FEOL) processing. It will be appreciated that amulti-layered substrate, of which an integrated circuit is an example,can be fashioned by multiple repeat steps and optionally also pre-steps.The present invention is being employed wherever an eBeam resist coatingof the invention is used at least once, or wherever a lithographic maskobtained by using said eBeam resist coating is used at least once, inthe method(s) of the invention.

The aforementioned processing options and features may apply equally toa method of manufacturing a lithographic mask (though features relatingto integrated circuit fabrication are obviously not especiallyapplicable to the creation of a lithographic mask), a method ofperforming lithography (using a lithographic mask formed by a method ofthe invention), a method of manufacturing a multi-layered substrate, ora method of fabricating an integrated circuit die or an integratedcircuit wafer comprising a plurality of integrated circuit dice.

Typically, step (vi) may be followed by one or more finishing steps,such as back-end-if-line (BEOL) processing (as used in the fabricationof integrated circuits). This may involve conductively interconnectingelectronic components and/or providing external contact terminals.

It will be evident that any number of pre-steps may precede step (i) ofthis method. In a particular embodiment, the input substrate is itself apartially built integrated circuit die (or wafer of dice) which hasalready been subjected to a plurality of pre-treatment steps.

Lithography Using Lithographic Masks Produced Using eBeam ResistCompositions of the Invention

As previously explained, eBeam resist compositions of the invention canbe used to produce a lithographic mask. The lithographic mask issuitably produced by the electron beam lithography methods of theinvention, which may optionally involve any further processing stepsrequired to provide the lithographic mask. The lithographic maskcomprises a mask pattern (which is suitably either a negative orpositive image of the intended ridge pattern of a pattern layer to beproduced using said mask). The mask pattern is suitably characterised byregions of surface/substrate transparency juxtaposed with regions ofsurface/substrate opacity. Such a mask is typically used in a method ofperforming lithography as defined herein (where step ii) involvesexposure via the lithographic mask). The combination of transparent andopaque regions of the mask suitably allows relevant radiation (forexposing a resist coating, whether one of the invention or not) to passthrough the transparent regions (and thereby expose a resist coating)and be blocked by the opaque regions (thereby leaving non-exposed resistcoating portions). The exposed resist coating may then be developed asusual to yield a resist pattern layer.

Since such lithographic masks benefit from the invention in that theycomprise a mask pattern of ultra high resolution, suitably ultra highresolution resist pattern layers can be produced using said masks. Suchmasks may be used in any of the methods defined herein, in conjunctionor in the absence of steps involving an eBeam resist coating of theinvention.

In an aspect of the invention, there is provided a lithographic maskwith a mask pattern having a resolution as defined herein in relation toa product obtained from electron beam lithography.

Most suitably the lithographic mask is a photomask, which is suitablefor use in photolithography (i.e. where the radiation is electromagneticradiation, suitably UV or visible light).

Integrated Circuit Wafers and Dice

The present invention provides a method of fabricating an integratedcircuit die or an integrated circuit wafer comprising a plurality ofintegrated circuit dice, the or each die comprising a plurality ofelectronic components, wherein the method comprises:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate; and    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;        -   OR    -   iii) providing a resist-coated substrate or applying a resist        coating to a substrate (the resist coating may be any resist        coating suitable for exposing via a lithographic mask, e.g. a        photoresist); and    -   iv) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;        -   AND    -   iii) developing the exposed (eBeam) resist coating to generate        an (eBeam) resist pattern layer, the (eBeam) resist pattern        layer comprising: developer-insoluble coating portions of the        (eBeam) resist coating (i.e. ridges); and an array of grooves        extending through the (eBeam) resist pattern layer;    -   iv) modifying the substrate, substrate surface, or part(s)        thereof, underlying the (eBeam) resist pattern layer (this may        involve conductively interconnecting the electronic components        of the or each die with conductor(s));    -   v) removing the (eBeam) resist pattern layer to provide a        modified substrate;    -   vi) optionally repeating, one or more times, step iv) and/or        steps i)-v) (with either a resist coating of the invention or an        alternative resist coating, such as a photoresist; and        optionally using electron beam radiation with or without a        lithographic mask or alternative radiation during exposure, such        as visible or ultraviolet light) upon the modified substrate;    -   vii) optionally conductively interconnecting the electronic        components of the or each die with conductor(s) (if not already        performed during one or more substrate/substrate-surface        modifying steps) to provide an integrated circuit with external        contact terminals;    -   viii) optionally performing one or more further finishing steps;    -   ix) optionally separating an integrated circuit die from a wafer        comprising a plurality of integrated circuit dice.

Step (i) of the method is optionally preceded by performing steps (i) to(vi) of this method (i.e. pre-steps (i)-(vi), optionally using either ofthe two step (i)/(ii) combinations) and/or performing steps (i) to (vi)of the method of performing electron beam lithography, optionallyrepeated one or more times, using either an eBeam resist coating or analternative resist coating and using either electron beam radiation oralternative radiation during exposure.

The eBeam resist coating suitably comprises an optionally dried and/orcured resist composition; wherein the eBeam resist composition comprisesan anti-scattering compound.

In a particular embodiment, steps (i) and (ii) comprise:

-   -   i) providing an (eBeam) resist-coated substrate as defined        herein or applying an (eBeam) resist coating to a substrate; and    -   ii) exposing part(s) of the (eBeam) resist coating to electron        beam radiation to provide an exposed (eBeam) resist coating;

In a particular embodiment, steps (i) and (ii) comprise:

-   -   i) providing a resist-coated substrate or applying a resist        coating to a substrate (the resist coating may be any resist        coating suitable for exposing via a lithographic mask, e.g. a        photoresist); and    -   ii) exposing part(s) of the resist coating, through a        lithographic mask (e.g. photomask) as defined herein (or        obtainable by a method defined herein), to radiation (e.g. UV or        visible light) to provide an exposed resist coating;

Features, including optional, suitable, and preferred features, relatingto this method of fabricating an integrated circuit die or an integratedcircuit wafer comprising a plurality of integrated circuit dice aredescribed in relation to a method of performing electron beamlithography hereinbefore.

However, it is important to appreciate that the fabrication ofintegrated circuit dies or dice may involve many processing steps, andmay involve the production of a multi-layered substrate.

As will be appreciated by those skilled in the art, producing anintegrated circuit (for inclusion in a circuit board) typically involveswafer processing (i.e. processing of a silicon wafer), die preparation(e.g. cutting/separating individual dice from the processed wafer),integrated circuit packaging (where each dice is package so that it maybe used in an circuit board), and suitably also integrated circuittesting.

Though wafer processing is well understood in the art, it is worthnoting that in certain embodiments wafer processing comprises wetcleaning; photolithography; ion implantation; dry etching and/or wetetching; plasma ashing; thermal treatment (e.g. annealing or thermaloxidation); chemical vapour deposition (CVD), physical vapour deposition(PVD), molecular beam epitaxy (MBE), and/or electrochemical deposition(ECD); wafer testing (e.g. to validate electrical performance); andwafer backgrinding (to reduce thickness of the wafer and resulting dieand chip). The methods, resist compositions/coatings, and lithographicmasks of the invention are suitably used at least once during waferprocessing. Where an eBeam resist coating is used during waferprocessing, suitably at least one photolithography operation (whichcombines substrate resist coating, exposure, and development) isreplaced by an electron beam lithography operation that uses an eBeamresist coating of the invention in place of a photoresist. Where alithographic mask, produced using an eBeam resist coating of theinvention (i.e. one characterised by the levels of resolution onlyachievable using the invention), is used during wafer processing,suitably at least one photolithography operation is replaced by alithography operation (which may itself involve photolithography or anyother type of lithography, including eBeam, though most preferablyphotolithography) that utilises said lithographic mask during exposure.However, it will be appreciated that the benefits of the invention maybe realised even if the eBeam resist coating or lithographic mask of theinvention is used only once (or to produce only a single layer or only asingle electronic component or single set of electronic components), andconceivably any further lithography operations (e.g. photolithography)may employ standard techniques known in the art of fabricatingintegrated circuits. Hence the methods of the invention provide theoption for any or all repeat steps (and even any or all of anypre-steps) to be performed without the coating or lithographic mask ofthe invention.

As aforementioned, steps (i)-(vi) of the method may constitutefront-end-of-line (FEOL) processing. Optionally, this processing does,at least to an extent, involve conductively interconnecting theelectronic components of the or each die. However, most suitably, stepsvii) to ix) constitute back-end-of-line (BEOL) processing.

Suitably conductively interconnecting the electronic components involvesmetallisation. Suitably, conductively interconnecting the electroniccomponents involves creating metal interconnecting wires isolated by oneor more dielectric (i.e. insulating) layers, where the insulatingmaterial is typically silicon dioxide (typically formed by thermaloxidation of silicon) or a silicate glass, though the material is notlimited.

Metallisation may involve generating a network of metal wires, such ascopper or aluminium wires. Such a process may suitably involve: a)blanket coating of a modified substrate with a metal (e.g. copper oraluminium), patterning (e.g. using lithography to generate a resistpattern layer), etching the metal underlying a resist pattern layer(i.e. to produce discrete metal wires), and forming or depositing aninsulating material over the metal wires. It will be appreciated that,for instance, where multiple layers of metal wires are required togenerate a viable integrated circuit, some or all of such metal wirelayers may be formed instead during a surface modification step, whichmay involve this same procedure.

After a wafer of dice is produced, die cutting may ensure to separateall of the dies ready for packaging.

Wafers and dice produced by the method of the invention arecharacterised by high performance owing, not least, to the highresolutions obtained. They may also be smaller than standard IC dice.

Integrated Circuit Packages

The skilled person in the field of integrated circuits is well able,using standard workshop techniques, to produce an integrated circuitpackage from an integrated circuit die. However, the present inventionprovides an a method of manufacturing an integrated circuit package, theintegrated circuit package comprising a plurality of pins and anintegrated circuit die with external contact terminals conductivelyconnected to the corresponding plurality of pins, wherein the methodcomprises:

-   -   i) providing an integrated circuit die as defined herein or        fabricating an integrated circuit die by a method of fabricating        an integrated circuit die as defined herein;    -   ii) attaching the integrated circuit die to a package substrate,        wherein the package substrate comprises electrical contacts,        each of the electrical contacts being optionally connected or        connectable to a corresponding pin;    -   iii) conductively connecting each of the external contact        terminals of the integrated circuit die to corresponding        electrical contacts of the package substrate;    -   iv) optionally (and if necessary) connecting the electrical        contacts of the package substrate to corresponding pins;    -   v) encapsulating the integrated circuit die.

Conductively Connecting Die and Package Substrate

Typically the method involves conductively connecting a die to a packagesubstrate by one of a variety of methods known in the art, such as wirebonding, thermosonic bonding, flip chip, wafer bonding, or tab bonding.

Connecting pins render IC's practical and straightforward to incorporateinto a circuit board. Therefore, the method suitably involveelectrically connecting the IC package pins to the die via appropriatecontacts. Typically, the connecting pins are part of an encapsulationdevice, and so this step may be combined with encapsulation step.

Dice can be air/moisture sensitive, hence why they are usuallyencapsulated. An encapsulated IC package is suitably baked, plated,laster marked, and trimmed. Finally, an IC package is suitablyelectronically tested for quality assurance.

Circuit Boards, Electronic Devices or Systems

Suitably, a circuit board incorporating an integrated circuit package(with a plurality of pins) of the invention may be readily produced bysimply conductively connecting the integrated circuit package to acircuit board.

Furthermore, said circuit board may be readily incorporated into anelectron device or system as defined herein. As such, consumer productsthat are or incorporate an electronic device or system of the invention,reap the benefits of the high resolution (and other notable advantages)integrated circuits afforded by methods of the invention, and the novelresist coatings described herein.

EXAMPLES Materials and Equipment

Unless stated otherwise, all reagents and solvents were commerciallyavailable and used as received. Elemental analyses were performed bydepartmental services at The University of Manchester. Carbon, nitrogenand hydrogen analysis was performed using a Flash 200 elementalanalyser. Metal analysis was performed by Thermo iCap 6300 InductivelyCoupled Plasma Optical Emission Spectroscopy (ICP-OES).

Poly(methmethylacrylate) (PMMA) (Mw ˜996 kDa) was obtained from SigmaAldrich.Poly(methmethylacrylate) (PMMA) was used as the resist polymer(or base polymeric component), though the skilled person will appreciatethat this is one of many suitably resist polymers that may beeffectively used in conjunction with the invention.

Pentaerythritol tetraacrylate was obtained from Sigma Aldrich.Pentaerythritol tetraacrylate was used as a crosslinker in negative toneresist compositions.

Silicon wafer substrates (wafers 500 μm thick) 10 mm×10 mm werecommercially sourced from University wafer.com and used as supplied.

The spin-coating equipment included an SCS G3P-8 spin coater, with an 8inch bowl and spin speeds of 100 to 10000 rpm.

A FEI Sirion Scanning Electron Microscope (SEM) was used to provide asource of an electron beam.

Post-developed patterned substrates were inspected and analysed using aLeica optical microscope using a 1 Ox objective lens.

Example 1—Formation of eBeam Resist Composition

In general, an eBeam resist composition of the invention may produced byforming a composition that includes an anti-scattering compound asdefined herein. Suitably the composition also comprises a coatingsolvent to enable the anti-scattering compound to be applied as a resistcoating.

Since the anti-scattering compound suitably includes a low-density, highmolecular weight polymetallic cage (since such structures produce lessscattering and secondary electrons from primary electron impacts, owingto the amount of empty space within such cage structures), anypolymetallic cage may be used to obtain the relevant beneficial effect,as justified in view of the predictive models disclosed herein. By wayof guidance to the skilled person, suitable structures may include anypolymetallic cage complexes the same or similar to those disclosed in G.F. S. Whitehead, F. Moro, G. A. Timco, W. Wernsdorfer, S. J. Teat and R.E. P. Winpenny, “A Ring of Rings and Other Multicomponent Assemblies ofClusters”, Angew. Chem. Int. Ed., 2013, 52, 9932-9935. This literaturedescribed the synthesis of such polymetallic cages, and it would bestraightforward for the skilled person to adapt the procedures disclosedtherein to produce a wide range of potential anti-scatterinng compounds.Moreover, the list of references appended hereto also provide enablingdisclosures of relevant compounds that may serve as antiscatteringcompounds of the invention.

Generally, the polymetallic cages are formed by mixing the relevantinorganic salts (containing the metal(s) intended for incorporation intothe cages) with the relevant ligands, typically carboxylic acids alongwith a fluoride salt (for example through an adaptation of theprocedures disclosed in G. A. Timco et al, Nat. Nanotechnol. 2009, 4,173-178). In some cases the polymetallic cages can act as a Lewis acid(i.e. capable of co-ordinatively accepting one or more electron pairs),and can be mixed with a suitable complementary Lewis base linker (e.g.pyridyl-substitute porphyrin) to produce an overall complex, suitably inwhich a plurality of the metal cages surrounds the linker.Alternatively, the polymetallic cages can act as a Lewis base (i.e.capable of co-ordinatively donating one or more electorn pairs),suitably by virtue of basic moieties present within one or more of theassociated ligands of the cage, and can be mixed with a suitablecomplementary lewis acid linker (e.g. optionally another metal-centeredcage structure which is either Lewis acidic or has substitutableligands). Suitably the Lewis acid and Lewis base components of theanti-scattering compound may be mixed in a stoichiometric ratio thatproduces a linker surrounded by a desired number of primary metalcomplexes.

However, in this disclosure we consider a number of specific examples inorder to illustrate the inventive concepts and broad applicability ofthe invention.

Example 1A—Preparation of [H₂NR₂][Cr₇NiF₈(Pivalate)₁₅(Iso-Nicotinate)]Complex, Along with Anti-Scattering Compounds and Resist CompositionsThereof

The primary metal complex, [H₂NR₂][Cr₇NiF₈(pivalate)₁₆] metal cagecomplex, can be produced by co-mixing 28 mole equivalents of chromium(III) fluoride with 2.7 mole equivalent of nickel (II) inorganic saltand 137 mole equivalents of pivalic acid in the presence of 11 moleequivalents of a secondary amine, suitably di-propylamine. Amodification of the procedure disclosed in F. K. Larsen et al.,Synthesis and Characterisation of Heterometallic {Cr₇M} Wheels, Angew.Chem. Int. Ed. 42, 101-105 (2003).

[H₂NPr₂][Cr₇NiF₈(pivalate)₁₆]. CrF₃.4H₂O (5.0 g, 27.6 mmol),[Ni₂(H₂O)(O₂CCMe₃)₄(HO₂CCMe₃)₄] (2.0 g, 2.7 mmol), dipropylamine (11.0mmol) and pivalic acid (14.0 g, 137.1 mmol) were heated with stirring at140° C. for 5 h. During this time chromium fluoride dissolved and agreen crystalline product formed. The flask was cooled to roomtemperature and 50 m1 of acetone added with stirring. The crystallineproduct was filtered, washed with a large quantity of acetone, dried inair and recrystallized from toluene to give[H₂NPr₂][Cr₇NiF₈(pivalate)₁₆]. Yield: 6.45 g (70.1%). Elemental analysis(%): calcd for C₈₉H₁₆₀Cr₇F₈N₁Ni₁O₃₂: Cr, 15.62, Ni, 2.52, C, 45.86, H,6.92, N, 0.60, F, 6.52. found: Cr, 15.17, Ni, 2.47; C, 46.38, H, 7.07;N, 0.5; F, 6.57. ES-MS (THF): m/z: −2191 [Cr₇NiF₈(O₂CCMe₃)₁₆]⁻; +2239M⁺.

The primary metal complex [H₂NR₂][Cr₇NiF₈(pivalate)₁₅(iso-nicotinate)]can be produced by co-mixing 1 molecule equivalent of[H₂NR₂][Cr₇NiF₈(pivalate)₁₆] and excess iso-nicotinic acid. Amodification of the procedure disclosed in G. A. Timco, et al.,Engineering coupling between molecular spin qubits by coordinationchemistry. Nature Nanotechnology 4, 173-178 (2009) may be used.

[H₂NPr₂][Cr₇NiF₈(pivalate)₁₆] (5.0 g 2.18 mmol), iso-nicotinic acid (0.8g 6.5 mmol) and n-propanol (150 mL) were refluxed for 24 h with constantstirring. The resulting solution was cooled to room temperature andfiltered. The solvent from the filtrate was removed under reducedpressure and the residue was washed with a large quantity ofacetonitrile. The residue was then dissolved in diethyl ether (˜300 ml).The obtained solution was filtered and the diethyl ether was removed bydistillation leaving a solid which was dissolved in pentane (˜200 ml).The pentane extract was filtered and evaporated to dryness giving agreen solid which still was a mixture of products. Further purificationof [H₂NPr₂][Cr₇NiF₈(pivalate)₁₅(iso-nicotinate)] was performed by columnchromatography on 40-63 μm mesh silica gel (BDH). First toluene was usedas solvent, which allowed un-reacted [H₂NPr₂][Cr₇NiF₈(pivalate)₁₆] to beeluted, leaving the products of the reaction at the top of the column.Thereafter a mixture of toluene:ethyl acetate elution was used. With amixture of toluene: ethyl acetate 24/1 the remains of 1 were eluted.Pure [H₂NPr₂][Cr₇NiF₈(pivalate)₁₅(iso-nicotinate)] was obtained as thesecond band starting its elution with a 13.5/1 ratio and finishing witha 10/1 ratio toluene/ethyl acetate mixture. Alternatively, pure[H₂NPr₂][Cr₇NiF₈(pivalate)₁₅(iso-nicotinate)] can be eluted (also after[H₂NPr₂][Cr₇NiF₈(pivalate)₁₆]) as the second band with a 20/1 hexane (orpetroleum ether)/ethyl acetate mixture. The solvents then evaporatedunder reduced pressure. Yield: 1.2 g (24%).

Elemental analysis, calcd (%) for C₈₇H₁₅₅Cr₇F₈N₂Ni₁O₃₂: Cr, 15.72, Ni,2.53, C, 45.12, H, 6.75, N, 1.21. Found: Cr, 15.97, Ni, 2.56, C, 44.90,H, 6.90, N, 1.19. ES-MS (sample dissolved in THF, run in MeOH): +2374[M+Na+2H₂O)]⁺ (100%); +2338 [M+Na]⁺; +2315 [M]⁺.

The Cr₇Ni(pivalate)₁₆ metal cage complex, which suitably acts as a Lewisacid, may then be mixed with a variety of Lewis base linker components(in this case a central electron-donating hub) to produce variousantiscattering compounds of different molecular weight, density, andmean ionisation potential. The mixture is then concentrated to affordthe final anti-scattering compound, which includes a relevant linker(e.g. porphyrin) surrounded by a number of the metal cages.

To form the resist composition, the anti-scattering compound isdissolved in hexane (22 mg of compound for every 1 g hexane) by mixingit with hexane and shaking the mixture at 15000 rpm using a IKA shakerfor 2 minutes.

Since a variety of linkers are used to form this particular series ofanti-scattering compounds, a variety and molecular weights and densitieswere observed, all of which are detailed below in Example 2A.

Example 1B

[GW20-14]—Preparation of[{Ni12(Chp)12(O2CMe)12(H2O)6}{NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6]Anti-Scattering Compounds and Resist Compositions Thereof

The primary metal complex and its associated dipropylammoniumcountercation [NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)] was prepared by themethod given in G. A. Timco, et al., Engineering coupling betweenmolecular spin qubits by coordination chemistry. Nature Nanotechnology4, 173-178 (2009). This represents a salt of a primary metal complex.This particular primary metal complex may serve as a lewis base to alewis acidic linker.

The linker compound [Ni12(chp)12(O2CMe)12(H2O)6}(THF)6] was prepared bythe method given in H. Andres, et al., Studies of a nickel-based singlemolecule magnet. Chem. Eur. J. 8, 4867-4876 (2002). This particularlinker compound serves as a Lewis acidic linker, since the THF (solvent)ligand associated with the nickel ions can be substituted, in this caseby the primary metal complex which may co-ordinate with the nickel ionsof the linker via the O2C—C5H4N (isonicotinate) ligand of the primarymetal complex.

The anti-scattering compound[{Ni12(chp)12(O2CMe)12(H2O)6}{[NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6]may then be prepared by mixing the aforementioned linker compound (25.2mg, 0.007 mmol) suspended in acetone (5 mL) with the aforementionedprimary metal complex salt (0.1 g, 0.043 mmol) in hot acetone (15 mL)with stirring. The mixture is heated for 15 minutes, during which timethe solution goes clear and subsequently a precipitate is formed. Thisis removed from the heat and left to stir overnight. The precipitate isthen collected, washed with hot acetone and extracted in ether. Thesolvent is removed under reduced pressure and the resultant powderrecrystallised from vapour diffusion MeCN into Toluene. Large, welldefined crystals suitable for single crystal XRD are collected andweighed. Yield: 97.5 mg (0.0058 mmol, 79.8% based on the linker);Elemental analysis calculated (%) for C606H1026Cl12Cr42F48N24Ni18O234:C42.92, H, 6.03, N, 1.98, Cr, 12.88, Ni, 6.23. Found: C, 42.08, H, 5.92,N, 1.76, Cr, 12.52, Ni, 6.16.

To form the resist composition, the anti-scattering compound isdissolved in hexane (22 mg of compound for every 1 g hexane) by mixingit with hexane and shaking the mixture at 15000 rpm using a IKA shakerfor 2 minutes.

Example 1C

Preparation of [7]Rotaxane Anti-Scattering Compounds and ResistCompositions Thereof

To a solution of 1,12-diaminododecane (0.7 g, 3.5 mmol) in methanol (30mL), 4-methylthiobenzaldehyde (0.47 mL, 3.5 mmol) in methanol (5 mL) wasadded and the reaction mixture was refluxed for 3 hr under nitrogenatmosphere and then cooling to room temperature. NaBH₄ was added andreaction mixture stirred over night under nitrogen atmosphere. Thereaction was quenched with water and evaporated. The solid was extractedwith chloroform, washed with water and dried over anhydrous magnesiumsulphate and evaporated. To a solution of the amine in methanol (30 mL),1 (0.64 mL, 3.5 mmol) in 5 mL methanol was added and the reactionmixture was refluxed for 3 hr under nitrogen atmosphere, allowed to stirat room temperature overnight. NaBH₄ was added and reaction mixturestirred over night under nitrogen atmosphere. The reaction was quenchedwith water and evaporated. The solid was extracted with chloroform,washed with water and dried over anhydrous magnesium sulphate andevaporated (60% yield). The product A was recrystallized from methanoland confirmed by spectroscopic analysis. ES-MS (sample dissolved indichloromethane, run in MeOH): m/z=504 [M+H]⁺. ¹H NMR (400 MHz, 293K,CDCl₃): □□=1.2-1.6 (m, 20H), 2.3 (s, 3H), 2.4-2.6 (m, 4H), 3.7 (s, 2H),3.8 (s, 2H), 7.1-7.3 (m, 4H), 7.3-7.5 (m, 4H), 7.6 (d, 2H), 8.6 (d, 2H).

Synthesis of [3]Rotaxane B

Me₃CCO₂H (24 g, 230 mmol), thread A (0.47 g, 0.94 mmol), CrF₃.4H₂O (2.36g, 13 mmol) and ZnCO₃ (1.5 g, 4.47 mmol) were heated at 140° C. withstirring in a Teflon flask for 1 h, then the temperature of the reactionwas increased to 160° C. for 24 h under N₂. The flask was cooled to roomtemperature, and then acetonitrile (35 mL) was added while stirring. Thegreen microcrystalline product was collected by filtration, washed witha large quantity of acetonitrile, dried in air, and then extracted withtoluene. Flash chromatography (toluene then toluene/ethyl acetate 7/3)afforded the desired [3]-rotaxane B as a green crystalline solid (1.1 g)in 23% yield. Elemental analysis (%) calcd forC₁₉₂H₃₃₅Cr₁₄F₁₆N₃Zn₂O₆₄S₁: Cr, 14.84, Zn, 2.66, C, 47.02, H, 7.37, N,0.85. found: Cr, 13.92, Zn, 2.39, C, 47.71, H, 6.88, N, 0.77.

[Fe₂Co(C₄₅H₁₈O₈₄)] (0.14 g, 2.86 mmol) was added to a solution of the[3]rotaxane B (0.01 g, 0.95 mmol) in hot acetone (10 mL), and themixture was refluxed for 5 min. and then stirred at r.t. for 4 h. Yield:0.05 g (20%). Elemental analysis (%) calcd forC₆₀₆H₁₀₅₉Cr₄₂F₄₈N₉Zn₆O₂₀₅CoS₃Fe₂: Cr, 14.0, Zn, 2.53, Co 0.38, Fe 0.79,C, 46.94, H, 6.88, N, 0.81. found: Cr, 12.76, Zn, 2.02, Co 0.48, Fe0.91, C, 47.23, H, 7.93, N, 0.82.

To form the resist composition, the anti-scattering compound isdissolved in hexane (22.5 mg of compound for every 1 g hexane) by mixingit with hexane and shaking the mixture at 15000 rpm using a IKA shakerfor 2 minutes.

Example 1D

[GT188-13]—Preparation of (CH₅₆H₃₂MgN₁₆ ²⁺)[Cr₇NiF₈(O₂CR_(B1))₁₆]₈Anti-Scattering Compounds and Resist Compositions Thereof

The primary metal complex, [Cr₇NiF₃(O₂CR_(B1))₁₅((Gluc-NH—R_(O1))(H₂O)]metal cage complex (R_(B1)=t-butyl), can be produced by co-mixing 33mole equivalents of chromium (III) fluoride with 2 mole equivalent ofnickel (II) inorganic salt, and 294 mole equivalents of pivalic acid(i.e. R_(B1)=t-butyl) and 17 mole equivalents of N-methyl-D-glucamine. Amodification of the procedure disclosed in G. A. Timco, et al.,Heterometallic Rings Made from Chromium Stick Together Easily, Angew.Chem. Int. Ed. 47, 9681-9684 (2008) may be used. This particular primarymetal complex may serve as a lewis acid to a lewis base linker.

Chromium(III) fluoride tetrahydrate (6.0 g, 33 mmol),N-ethyl-D-glucamine (3.6 g, 17 mmol), pivalic acid (30.0 g, 294 mmol)and nickel(II) carbonate hydroxide tetrahydrate (1.2 g, 2.0 mmol) wereheated together with constant moderate stirring in a Teflon flask at160° C. for 34 h. After the first 2 h of the reaction the solid whichhad formed in the flask was broken into small pieces using a spatula.This procedure was repeated twice more during the following 4 h. At theend of the reaction a solid has formed. The reaction is cooled to RT andEt₂O (100 mL) was added with stirring and the resulting solution wasfiltered. The filtrate was diluted slowly with stirring with MeCN (˜170mL) and a microcrystalline violet product started to precipitate duringthis time. The flask was sealed and kept at −10° C. for 2 days. Thecrystalline product was collected, washed with a mixture of Et₂O: MeCN(1:1) and dried in air. This product was purified from a very fine brownpowder by column chromatography on 40-63 μm mesh silica gel (BDH). 1 waseluted with Et₂O as the first main band leaving a brown band on thecolumn. The solvent was then evaporated under reduced pressure and thesolid dissolved in Et₂O (˜50 mL) and the solution diluted with MeCN (˜50mL). The crystalline product started to form immediately. The flask waskept at −10° C. for one day, then the crystals were collected byfiltration, washed with a mixture of Et₂O: MeCN (1:2) and dried in air.Yield 3.2 g (30%, based on Cr). Elemental analysis calcd (%) forC₈₃H₁₅₁Cr₇NiF₃N₁O₃₆: Cr, 16.40, Ni, 2.65, C, 44.93, H, 6.86, N, 0.63.found: Cr, 16.40, Ni, 2.54, C, 44.42, H, 7.11, N, 0.55.

ES-MS (sample dissolved in Et₂O, run in MeOH): +2200 [M]⁺ (100%); +2223[M+Na]⁺.

The linker compound salt(2,3,7,8,12,13,17,18-Octakis(4-pyridyl)porphyrazinato)magnesium(II),[Mgpz(pyr)8] (C56H32N16Mg) thereof shown below was prepared by M. E.Anderson, A. G. M. Barrett, B. M. Hoffman, Inorg. Chem. 1999, 38,6143-6151. This particular linker compound serves as a Lewis baselinker, whose pyridine lone pairs co-ordinate with the metal centre(s)of the primary metal complex.

Preparation of [(Cr₇NiF₃(Meglu)(O₂C^(t)Bu)₁₅)]₈[Mgpz(pyr)₈]:

[Cr₇NiF₃(Meglu)(O₂C^(t)Bu)₁₅(H₂O)] where H₅Meglu=N-Methyl-D-glucamine;was prepared similarly [Cr₇NiF₃(Etglu)(O₂C^(t)Bu)₁₅(H₂O)] whereH₅Etglu=N-Ethyl-D-glucamine by the method given in E. Garlatti et al, J.Am. Chem. Soc. 2014, 136, 9763-9772, using H₅Meglu instead of H₅Etglu.

The linker compound salt [(2,3,7,8,12,13,17,18-Octakis(4 pyridyl)porphyrazinato) magnesium(II)], [Mgpz(pyr)₈]=(C₅₆H₃₂N₁₆Mg) was preparedby the method given in M. E. Anderson, A. G. M. Barrett, B. M. Hoffman,Inorg. Chem. 1999, 38, 6143-6151.

[Mgpz(pyr)₈] (0.14 g, 0.15 mmol) and [Cr₇NiF₃(Meglu)(O₂C^(t)Bu)₁₅(H₂O)](3.5 g, 1.59 mmol where stirred in dichloromethane (DCM) (250 mL) for 4days at room temperature (r.t.), then solvent (DCM) was removed underreduced pressure at caT=36° C. and residue stirred with acetone (100 mL)at ambient temperature for 24 h. Obtained precipitate was collected byfiltration and washed with acetone (3×25 mL). Then it was re-dissolvedin DCM (40 mL) and obtained solution filtered, and filtrate diluted withacetone (20 mL). After this the solvents where evaporated while stirringat r.t. in a flow of N₂. Obtained blue solid was dried en vacuo. Yield:2.1 g (77.5%, based on [Mgpz(pyr)₈]).

Elemental analysis (%): calc. for C₇₁₂H₁₂₀₈Cr₅₆F₂₄Mg₁N₂₄Ni₈O₂₈₀:Cr15.78, Ni, 2.55, C, 46.36, H, 6.60, N, 1.82. found: Cr, 16.17, Ni,2.50, C45.32, H, 6.88, N, 1.18.

The anti-scattering compound C₇₁₂H₁₂₀₈Cr₅₈F₂₄MgN₁₆Ni₈O₂₈₀ (C₅₆H₃₂MgN₁₆²⁺)[Cr₇NiF₈(O₂CR_(B1))₁₆]₈ may then be prepared by mixing one moleequivalent of the aforementioned linker (specifically a salt thereof)suspended in an appropriate solvent [acetone] with the aforementionedprimary metal complex (specifically a salt thereof) in an appropriatesolvent [acetone] with stirring. The mixture is heated for 15 minutes,during which time the solution goes clear and subsequently a precipitateis formed. This is removed from the heat and left to stir overnight. Theprecipitate is then collected, washed with hot acetone and extracted inether. The solvent is removed under reduced pressure and the resultantpowder recrystallised from vapour diffusion MeCN into Toluene.

To form the resist composition, the anti-scattering compound isdissolved in hexane (20 mg of compound for every 1 g hexane) by mixingit with hexane and shaking the mixture at 15000 rpm using a IKA shakerfor 2 minutes.

Example 1E [GT133-14]—Preparation of [NH₂Pr₂][Cr₇NiF₈(O₂CR_(B1))₁₆] mAnti-Scattering Compounds and Resist Compositions Thereof

The primary metal complex, [Cr₇NiF₈(O₂CR_(B1))₁₆] metal cage complex(where R_(B1)=C₅H₉; 1-methylbut-4-enyl), can be produced by co-mixing 7mole equivalents of chromium (III) inorganic salt with one moleequivalent of nickel (II) inorganic salt, 8 mole equivalents of fluoride(may be provided amongst other inorganic salts), and 16 mole equivalentsof 2-methylpent-4-enoic acid. This metal cage complex is prepared as thedipropylammonium salt. A modification of the procedure disclosed in F.K. Larsen et al., Synthesis and Characterisation of Heterometallic{Cr₇M} Wheels, Angew. Chem. Int. Ed. 42, 101-105 (2003) was used toprepare the primary metal complex with its associated dipropylammoniumcountercation [NH₂Pr₂][Cr₇NiF₈(O₂CR_(B1))₁₆] was prepared. For thepurposes of comparison this primary metal complex was in fact theanti-scattering compound, and was not associated with a linker.

To form the resist composition, the anti-scattering compound isdissolved in hexane (25 mg of compound for every 1 g hexane) by mixingit with hexane and shaking the mixture at 15000 rpm using a IKA shakerfor 2 minutes.

Example 2—Formation of eBeam Resist-Coated Materials

In general, eBeam resist-coated materials are formed through coating asubstrate, or part thereof, with an appropriate eBeam resistcomposition, and suitably thereafter drying and/or curing to form acoating.

Example 2A—Formation of Resist Coating with Cr₇Ni(2-Ethylhexanoate)₁₆Complex

As mentioned in Example 1A, this particular metal cage complex was usedto gauge a range of key properties, which would then be use inMonte-Carlo simulations to determine the suitability of variousanti-scattering compounds for use in high-resolution eBeam resists.Moreover, comparisons were made with standard resists (e.g. PMMA) andstandard IC substrates, e.g. silicon.

Resist-coated substrates were formed using a variety of anti-scatteringcompounds incorporating Cr₇Ni(2-ethylhexanoate)₁₆ metal cages (as perExample 1A) by systematically spin-coating a series of 10 mm×10 mmsilicon substrates (600 nm thick) with the relevant anti-scatteringcompounds. Each anti-scattering compound was dissolved in hexane toallow spin-coating of the corresponding resist composition. The resistwas spun using a spin cycle of 8000 rpm for 30 seconds, which wasfollowed by a soft-bake at 100° C. for 2 minutes, allowing the castsolvents to evaporate. All resist films resulted with a thickness of 100nm.

Table 1 therefore illustrates the relevant properties for a variety ofresist cpatomgs incorporating various proportions ofCr₇Ni(2-ethylhexanoate)₁₆ metal cages (i.e. so that density and MW maybe varied).

TABLE 1 Physical properties of the materials used in the Monte Carlomodel. Cr₇Ni(2- EthylHexanote)₁₆ Physical property PMMA complex SiliconDensity (g/cm³) 1.19 0.8 → 2   2.33 Effective Atomic Number 5.85 11.6 14Average Atomic Weight (g/mol) 100.116 2000 → 16000 28.0855 MeanIonization Potential (eV) 74 150 174

Example 2B—Formation of Resist Coating with[{Ni12(Chp)12(O2CMe)12(H2O)6}{[NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6]Anti-Scattering Compound

Resist-coated substrates were formed using a resist compositionincluding a[{Ni12(chp)12(O2CMe)12(H2O)6}{[NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6]anti-scattering compound in the same manner as described in Example 2A.Again the resist films resulted with a thickness of 100 nm.

Example 2C—Formation of Resist Coating with [7]Rotaxane Anti-ScatteringCompound

Resist-coated substrates were formed using a resist compositionincluding a [7]rotaxane anti-scattering compound in the same manner asdescribed in Example 2A. Again the resist films resulted with athickness of 100 nm.

Example 2D—Formation of Resist Coating with (C₅₅H₃₂MgN₁₆²⁺)[Cr₇NiF₈(O₂CR_(B1))₁₆]₈ Anti-Scattering Compound

Resist-coated substrates were formed using a resist compositionincluding a (C₅₆H₃₂MgN₁₆ ²⁺)[Cr₇NiF₈(O₂CR_(B1))₁₆]₈ anti-scatteringcompound in the same manner as described in Example 2A. Again the resistfilms resulted with a thickness of 100 nm.

Example 2E—Formation of Resist Coating with[NH₂Pr2][Cr₂NiF₈(O₂CR_(B1))₁₆] Anti-Scattering Compound

Resist-coated substrates were formed using a resist compositionincluding a [NH₂Pr₂][Cr₇NiF₈(O₂CR_(B1))₁₆] anti-scattering compound inthe same manner as described in Example 2A. Again the resist filmsresulted with a thickness of 100 nm.

Example 3—Formation of Exposed eBeam Resist-Coated Materials (i.e.e-Beam Exposure)

During these studies, all eBeam resist-coated materials are exposed inthe same manner: by directly writing onto the relevant coating with anelectron beam. The input current and voltage of the beam, and overalldosage delivered to the coating, may be judiciously adapted by theskilled person without undue burden.

In the present studies the exposure clearing doses of each resistmaterial was determined from a two 1-dimensional matrix of a singlepixel line by 20 μm, therefore the width of the line was the width ofthe electron beam. The first 1-dimensional matrix had each single pixelline separated by a pitch of 100 nm. These were exposed with a dosescale from 1 to 20.95 pC/cm in incremental steps of 0.05 pC/cm, while,the second 1-dimensional matrix had a pitch of 200 nm.

The dose scale was increased from a dose factor of 1 to 17.95 pC/cm withthe same incremental step as the 100 nm pitch. Test patterns were thenproduced. All resists were then exposed using a FEI Sirion ScanningElectron Microscope (SEM). The exposed pattern was written using anacceleration voltage of 30 keV, a probe current of 50 pA, the dwell timewas 12.12 μS and the step size was 6.1 nm. From these exposureparameters, the base dose was calculated to be 1000 pC/cm. Each patternwas exposed using a write field of 100 μm.

Example 4—Formation of Patterned Substrate (i.e. Developing ExposedResist Coating)

Each material was developed using a solution of Hexane, for 30 sfollowed by an N₂ blow dry.

All patterns fabricated in all of the resist were inspected using aLeica optical microscope using a 10× objective lens.

Example 5—Predictive Models Monte Carlo Simulation

The Monte Carlo simulation presented is based on the model developed byJoy (D. C. Joy, ‘Monte Carlo Modeling for Electron Microscopy andMicroanalysis’, pp. 33, Oxford University Press, (1995)). When electronsare incident on a resist film they are scattered elastically andinelastically with the molecule throughout the resist. These twoscattering events are governed by two different sets of equations.Elastic scattering is determined by the screened Rutherford crosssection,

$\begin{matrix}{{\sigma_{elastic} = {\frac{Z^{2}}{E^{2}}\frac{4\pi}{\alpha \left( {1 + \alpha} \right)}\left( \frac{E + 511}{E + 1024} \right)^{2}{cm}^{2}\text{/}{atom}}},} & (2)\end{matrix}$

where E is the electron energy in keV, Z is the atomic number of thematerial or if the material is a compound then the effective atomicnumber is used. α is the screening factor, this compensates for the factthat the electron does not ‘see’ the all of the atom's charge as it issurrounded by a cloud of electrons. The mean free path is calculatedfrom the scattering cross section is given by

$\begin{matrix}{{\lambda_{elastic} = \frac{A}{N_{a}{\rho\sigma}_{elastic}}},} & (3)\end{matrix}$

where A is the atomic weight of the material and Na is Avogadro'snumber. Inelastic scattering however, must use a different relationshipbecause there is a high probability that a secondary electron (SE) isproduced from this scattering event. Therefore, the inelastic scatteringcross section is calculated using,

$\begin{matrix}{{\frac{d\; \sigma_{inelastic}}{d\; \Omega} = {\frac{\pi \; e^{4}}{E^{2}}\left( \frac{1}{\Omega^{2} + \left( {1 - \Omega} \right)^{2}} \right)}},} & (4)\end{matrix}$

where ΩE is the energy of the secondary electron produced. The inelasticscattering event causes the primary electron to be deflected by an angleα given by

$\begin{matrix}{{{\sin^{2}\alpha} = \frac{2\Omega}{2 + t - {t\; \Omega}}},} & (5)\end{matrix}$

where t is the kinetic energy of the electron (in units of its restmass). However the secondary electron created exits the collision at anangle γ given by,

$\begin{matrix}{{{\sin^{2}\gamma} = \frac{2\left( {1 - \Omega} \right)}{2 + {t\; \Omega}}},} & (6)\end{matrix}$

Once the inelastic scattering cross section is calculated, the mean freepath of the electron must be calculated using,

$\begin{matrix}{{\lambda_{inelastic} = \frac{A}{N_{a}Z\; {\rho\sigma}_{inelastic}}},} & (7)\end{matrix}$

The total mean free path of the electron in resist is the sum of theelastic and inelastic mean free paths

$\begin{matrix}{\frac{1}{\lambda_{total}} = {\frac{1}{\lambda_{elastic}} + {\frac{1}{\lambda_{inelastic}}.}}} & (8)\end{matrix}$

From the value of the mean free path, the statistical distance theelectron will travel before it collides again can be calculated. This isachieved using the step size equation given by,

s=−λ ln(RND),  (9)

where λ is the total mean free path and RND is a random number between 0and 1. This gives a distribution of step sizes with an average step sizeof λ.

The final step of the Monte Carlo simulation is to calculate the energylost by the electron during the scattering event. This was done usingthe modified Bethe equation, which governs the stopping power of amaterial and is given by,

$\begin{matrix}{{\frac{dE}{dS} = {78500\frac{Z}{AE}{\ln \left( \frac{1.166\left( {E + {0.85J}} \right)}{J} \right)}}},} & (10)\end{matrix}$

where J is the mean ionization potential of the material. The meanionization potential describes the energy losses the electronexperiences in a given material, it can be calculated by,

$\begin{matrix}{{J = {{9.76(Z)} + \frac{58.5}{Z^{0.19}}}},} & (11)\end{matrix}$

Every time an electron scatters, this energy loss value is calculatedand subtracted from the current energy of the electron. Once theelectron's energy falls below 0.5 KeV, the electron was no longertracked as the distance it travels in the material is negligible.

For the inclusion of the nanocomposite material to the base material aweighted average distribution was used, here the percentage (by weight)of the two materials was compared to a random number generator tocalculate the material the electron effectively scatters off for eachstep.

σ_(total)=ωσ_(HAuCl) ₄ +(1−ω)σ_(PMMA),  (12)

where ω is the relative weight of the anti-scattering compound to PMMA.

The electron beam resists modeled here had thickness of 100 nm. Allresists systems are on 600 nm of Silicon and the physical properties ofone (GW20-14 of Example 1B) are given in Table 2.

TABLE 2 Physical properties of the GW20 - 14 molecules that was used inthe Monte Carlo model. GW20-14 is [{Ni12(chp)12(O2CMe)12(H2O)6}{[NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6] Physical property GW20 - 14Silicon [12] Density (g/cm³) 0.814 2.33 Effective Atomic Number 0.21 14Average Atomic Weight (g/mol) 16886.04 28.0855 Mean Ionization Potential(eV) 87.43 174

The density was experimentally determined from the unit cell contentsdetermined by X-ray diffraction (XRD) measurements and the effectiveAtomic number and the average Atomic weight of the each material wascalculated and also determined from the XRD measurements whereas, themean ionization potential was calculated from equation 11. The MonteCarlo simulation used here can be found in S. Lewis et al, ‘Influence ofnanocomposite materials for next generation nanolithography’, Advancesin diverse industrial applications of nanocomposite’, Intech, pp503-528, March 2011, and also in S. Lewis et al, ‘Characterization of anultra high aspect ratio electron beam resist for nanolithography’,Nanotechnology 2010: Electronics, Devices, Fabrication, MEMS, Fludics &Computational, Vol 2, pp 195-198.

The incident electron beam that the simulation used had a Gaussiandistribution of 30, where the spot size had a diameter of 3 nm. Thesimulation was run with a 100000 electrons and was run 1,000,000 timesand averaged to reduce the statistical error.

Results & Discussion

Results A—Tests Upon Resist Coatings ContainingCr₇Ni(2-ethylhexanoate)₁₅ Complex of Example 1A

A variety of experiments were conducted using the resist compositions ofExample 1A, and resist-coated materials of Example 2A, which arediscussed below.

It was shown by the Monte Carlo simulations that when the molecularweight of the Cr₇Ni(2-EthylHexanote)₁₆ complex was increased from 2000to 16000 g/mol the number of secondary electrons decreased from 12 to 0(when the density was 0.8 g/cm³), this can be seen in FIG. 1. However,by increasing the density (2 g/cm³) of the molecule gave rise to anincrease of secondary electrons generated of 8.5 times. This issignificant amount of secondary electrons within the resist as theseelectrons are responsible for exposing the resist laterally, thusbroadening the desired nanostructure and this is shown in FIG. 1.

FIG. 1 is a chart showing the number of Secondary Electrons generated ina 100 nm thick films at 30 KeV eBeam exposure for compounds of molecularweights shown as a function of density.

FIG. 1 shows a red cross surrounded by a red box, this exhibits the realparameters for the Cr₇Ni(2-EthylHexanote)₁₆ complex molecule (which isin fact [NPr₂H2][Cr₇NiF₈(2-EthylHexanote)₁₆]), where it has a molecularweight of 2968.02 g/mol and a density of 1.25 g/cm³. It can be clearlyseen that this molecule generates 13 secondary electrons, when comparingthis to PMMA where in previous studies it had been ascertained that itproduces 200 at the incident energy of 30 KeV [1]. Therefore the PMMAproduces approximately 15 times more secondary electrons. This issignificant, as this is related to the ultimate resolution that can bedetermined.

To produce the highest fidelity resolution the optimum materialparameters was found to have the largest molecular weight and the lowestdensity possible because to produce the highest resolution nanostructure the number of secondary electrons must be zero. This is thatcase when the molecular weight was 16000 g/mol and the density was 0.8to 1.15 g/cm³ respectively and this is indicated by the red box in FIG.3. This is the optimum material properties.

The observation seen in FIG. 2 illustrate that the primary electrons donot interact with molecule, as it has significant amounts of emptyspace. This is because the density of the Cr₇Ni(2-EthylHexanote)₁₆complex is smaller than that of the PMMA material, due to that the meanfree path between the atoms of the molecule is larger. Therefore, theprimary electrons (PE) will experience a reduced amount of collisions asit travels through the resist film. From this, It is evident that as themolecule weight of the Cr₇Ni(2-EthylHexanote)₁₆ complex is increased,the number of SE's that are generated decreases. This is because themolecular weight of the Cr₇Ni(2-EthylHexanote)₁₆ complex is large (above14000 g/mol) and governs a smaller the concentration of scatteringcenters (with the properties of a larger effective atomic number,density and ionization potential than that of the polymer) can beincorporated into the polymer film.

FIG. 2 is a chart showing a close up of FIG. 1, where the moleculeweight is varied from 10000 to 16000 g/mol. All conditions are the sameas FIG. 1.

As a consequence of this is that the primary electrons lose very littleamount of energy, for the case of Cr₇Ni(2-EthylHexanote)₁₆ complex it is150 eV per collision when compared to that of PMMA material, which is 74eV. Thus, the primary electrons are fast enough not to cause multipleinelastic scattering events and generate more and more SE. Therefore, itis expected that a large exposure dose is required because thestatistical chance of generating a secondary electron is extremely low.

As a comparison the GW20-14 ring of ring material (Example 1B, chemicalcomposition[{Ni12(chp)12(O2CMe)12(H2O)6}{[NH2Pr2][Cr7NiF8(O2CtBu)15(O2C—C5H4N)]}6]—it'smaterial parameters are density is 0.814 g/cm³, effective atomic numberis 4.4, molecular weight is 16886.02 g/mol and its ionization potentialis 87.43 eV) was spun directly on to a silicon substrate, this resultedwith a film of 100 nm thick. FIG. 3 shows a nano-grating pattern wasfabricated in PMMA and GW20-14 ring of ring structure. The PMMA materialproduced nanostructures with line widths of 50 nm, and this can be seenin FIG. 3a . Whereas, the GW20-14 ring of ring material resulted with apattern which exhibited line widths of 6.22 nm. This is a significantresult because it demonstrates that this material offers a resolution ofmore than 8 times that of PMMA for the same resist thickness.

FIG. 3 shows SEM images illustrating: a) 50 nm lines exposed in PMMAwith a dose of 774 pC/cm. The sample was developed with MIBK:IPA withthe ratio of 1:3. b) 6.22 nm lines exposed in GW20-14 with a dose of6200 pC/cm. The sample was developed with Hexane.

It was found that the GW20-14 material produced an increase in exposuredose. This gave rise to exposure dose of 6200 pC/cm, which is slower bya factor of 8 when compared to the industry standard PMMA, respectively.From this it can be ascertained that the exposure method was notcontributed by the presence of SE, as the molecule prohibits thecreation of secondary electrons. Therefore, the primary electrons areresponsible for the production of the pattern. This can be seen becausethe side wall profile appears to exhibit perpendicular angle of 90° whencompared to the Silicon. This was shown to show strong agreement withthe Monte Carlo simulation. Thus extrapolations from the Monte Carlosimulation of how other materials would behave in terms of theiranti-scattering properties are entirely credible and justified.

A metal organic negative tone electron beam resist have beeninvestigated using Monte Carlo Model. It was shown by the Monte Carlosimulations that the Cr₇Ni(2-EthylHexanote)₁₆ complex compound did notgenerate any secondary electrons when the molecular weight was 16000g/mol and the density was 0.8 to 1.15 g/cm³. This demonstrated strongagreement between the simulation and the experimental results because itwas shown that the GW20-14 ring of ring material resulted with a patternwhich exhibited line widths of 6.22 nm. This is a significant resultbecause it demonstrates that this material offers a resolution of morethan 8 times that of PMMA for the same resist thickness. It was foundthat to the produce these nano structures an exposure dose of 6200 pC/cmwas required. From this, it can be deduced that the primary electronsare responsible for the production of the pattern because the moleculeprohibits the generation of secondary electrons and therefore cannot bethe exposure method.

Results B-E—Tests Upon Resist Coatings Containing AntiscatteringCompounds Described in Examples 1B-1E

These studies demonstrate that the eBeam resists of the invention ensurethat the primary electrons are confined to the immediately write areaand as a consequence this constrains the lateral electron scattering ofthe secondary electrons (SE) thus, the highest resolution can beobtained. It was shown by the Monte Carlo simulations that NickelChromium cages decreased the amount of SE's significantly within thematerial and this is shown in FIG. 4.

FIG. 4 is a chart showing the internal electron scattering interactionsinside the Nickel Chromium ring like structured materials exposed to anacceleration voltage of 30 KeV. Secondary electrons and backscatteredelectrons are indicated in Red and Blue respectively.

FIGS. 5-9 show SEM micrographs of sub—30 nm structures that werefabricated with the GW20-14 (Ex. 1B), 7—Rotaxane (Ex. 1C), GT188-13 (Ex.1D) and GT133-14 (Ex. 1E) resists respectively.

FIG. 5 shows SEM images illustrating: (a) Profile view of 6.22 nm lineson a 200 nm pitch (tilt 70°). (b) Profile view of 10.4 nm lines on a 100nm pitch (tilt 70°). Dose is 6200 pC/cm. FIG. 5 shows the GW20-14material that had been patterned to produce a resolution of 6.22 and10.4 nm with a pitch of 200 and 100 nm respectively.

The aspect ratio seen here is 16:1 and 10:1 respectively. Thesenanostructures obtained show strong agreement with the predicationsproduced by the Monte Carlo simulation illustrated in FIG. 4.

From these observations, it can be deduced that the interaction betweenthe generation of SE's and the material cannot occur. This is becausethe density of the molecule is 0.814 g/cm3 and its molecular weight islarge (16886.04 g/mol). From this, most of the film is free space and asa consequence the primary electrons are constrained and cannot produceSE, therefore lateral electron scattering is prohibited. Hence, aresolution of 6.22 nm is achieved.

FIG. 6 shows an SEM image illustrating a profile view of 16.3 nm lineson a 200 nm pitch (tilt 70°). Dose is 6000 pC/cm. FIG. 6 shows theresultant nanostructures that were fabricated using the 7-Rotaxanematerial. From this material, nanostructures with line widths of 16.3 nmhave been demonstrated. In turn, this gave an aspect ratio of 6.1:1.Interestingly, despite the decreased resolution, the exposure doseremains consistent with the exposure dose that produced thenanostructures in the GW20-14 material.

FIG. 7 shows the resultant nanostructures that were fabricated using theGT188-13 material. From this material, nanostructures with line widthsof 13.9 nm have been demonstrated. In turn, this gave an aspect ratio of7.2:1. It has been noticed that the exposure dose has increaseddramatically.

FIG. 7 shows an SEM image of GT188-13 material illustrating a profileview of 13.9 nm lines on a 200 nm pitch (tilt 70°). Dose is 16850 pC/cm.

The nanostructures produced by the GT133-14 material can be seen in FIG.8. The GT133-14 material produced nanostructures with a resolution of26.1 nm and an aspect ratio of 3.8:1. The decreased resolution wasexpected because the 2-Methyl-4-Pentenoic acid was incorporated into themolecule to serve has a cross linker. This was preformed to increase tosensitivity of the material, which was approximately 2000 pC/cm. This isan improvement on previous materials presented in FIGS. 5-7.

FIG. 8 shows an SEM image of the GT133-14 material illustrating aprofile view of 26.1 nm lines on a 200 nm pitch (tilt 70°). Dose is 1000pC/cm.

The sensitivity was increased at the expense of resolution, this was dueto that the 2-Methyl-4-Pentenoic acid produces free radicals uponexposure and subsequently they produce SE. These electrons scatterlaterally and interact with the adjacent molecules and cross links themtogether forming a web like structure. Hence, the exposure dose is lowerwhile broadening the resultant resolution of the nanostructure.

FIG. 9 is a chart showing Resolution and Aspect ratio of eachantiscattering compound with a 200 nm pitch. FIG. 9 depicts the optimummaterial that produced the highest resolution and aspect ratio was theGW20-14. It is evident that as the resolution decreases the aspect ratiothat can be achieved also decreases.

It was found that the Nickel Chromium ring like structured materialsproduce an increase in resolution of 6.22 nm while exhibiting aspectratios larger than 10:1 at an accelerating voltage of 30 KeV, whilst the7-Rotaxane and GT188-13 material obtained a decrease in resolution andaspect ratio. This result is significant as this is not possible usingindustry standard polymeric type materials such as PMMA. This gave riseto exposure dose of 6200 pC/cm, which is slower by a factor of 8 whencompared to the industry stand PMMA. From this it can be ascertainedthat the exposure method was not contributed by the presence of SE, asthe molecule prohibits the creation of secondary electrons. Therefore,the primary electrons are responsible for the production of the pattern.This can be seen because the side wall profile appears to exhibitperpendicular angle of 90° when compared to the Silicon. This was shownto show strong agreement with the Monte Carlo simulation.

When the sensitivity of these materials was increased by a factor of6.2, the resolution decreased significantly. This was attributed by thegeneration of secondary electrons scattering at an angle of 80° andbroadening the resultant nanostructure. Secondary electrons weregenerated from the 2-Methyl-4-Pentenoic acid present in the molecule.Therefore, this confirms the role of secondary electrons.

Further Results Relating to GW20-14 (of Example 1B)

It is evident from FIG. 10 that the primary electrons are confined tothe immediate write area. This would suggest that a large exposure doseis required for the GW20-14 resist. This is because the density of theGW20-14 is smaller (0.814 g/cm³, where conventional polymeric resistsare 1.2 g/cm³ and above) than conventional resist materials such asPMMA, this is attributed to that the mean free path between the atoms ofthe molecule is large due to the free space inside the Nickel Chromiumring like structure.

FIG. 10 is a chart showing the internal electron scattering interactionsinside GW20-14 using 30 KeV acceleration voltage. Secondary electronsand backscattered electrons are indicated in Red and Blue respectively.

It can be seen from FIG. 10 that little energy is lost from the PE thatthe likely hood of creating a SE is very small. Moreover, the diameterof the molecule was measured to be 4.4 nm by 2.8 nm thick, this leads toa molecular weight of 16886.02 g/mol. The significance of this is thatthe molecule is large and the PE will not ‘see’ the entire molecule andcan only scatter from the top and bottom surface of the cage. As theGW20-14 film thickness is 100 nm and thickness of the molecule is 2.8nm. Therefore, there are approximately 35 molecules on top of each other(in the z-direction) and from this there are only approximately 72scattering points that the PE can scatter from. Hence, this leads to asmall chance of generating an inelastic scattering event. Of course, aSE can be created if the concentration of the PE inserted into the filmis increased; from this a large exposure dose is expected.

FIG. 11 is a chart showing the number of Secondary Electrons generatedin a 100 nm thick GW20-14 film.

FIG. 11 shows the number of SE generated inside the GW20-14 resist film.It is evident that at the lower energies of 10 to 50 KeV, the PE is slowenough to cause multiple inelastic scattering events and generate moreand more SE, this is expected from equations 4 and 6. However, at thelarger energies of 50 KeV to 100 KeV, the incident electron has moreenergy associated with it, and therefore, to generate a secondaryelectron it needs to have more collisions with the atoms in the resistmaterial to lose most of its energy to generate a SE. However, as thefilm is a 100 nm thick, there are not enough atoms in the film (in the zdirection) to scatter off to lose a large proportion of its energy. Theconsequence of this is that the a substantial number of PE's will cometo rest deep into the silicon substrate below or they will be backscattered into the underside of the resist material, approximately 30-40μm away from the immediate exposure area. Thus, higher resolution can beachieved by exposing the resist with 100 KeV tool by confining theforward scattering electrons to the incident beam inside the resist, butat the expense of larger writing times. Currently, 50 KeV tools areemployed by the semiconductor industry. This is because it is seen thatthe threshold of resolution vs writing times is at this accelerationvoltage, and reflects this philosophy, as the number of SE created isrelatively constant.

FIG. 12a and FIG. 12b show the GW20-14 material that had been patternedto produce a resolution of 6.22 and 10.4 nm with a pitch of 200 and 100nm respectively. The aspect ratio seen here is 16:1 and 10:1respectively. These nanostructures obtained show strong agreement withthe predications produced by the Monte Carlo simulation illustrated inFIG. 10. From these observations, it can be deduced that the interactionbetween the generation of SE's and the material cannot occur. This isbecause the density of the molecule is 0.814 g/cm³ and its molecularweight is large (16886.04 g/mol). From this, most of the film is freespace and as a consequence the primary electrons are constrained andcannot produce SE, therefore lateral electron scattering is prohibited.Hence, a resolution of 6.22 nm is achieved.

To produce these nanostructures the exposure doses required was 6200 and9950 pC/cm. This was expected because the results of the simulationshown in FIG. 4 predicted that the probability of generating a SE isvery small. It is well known that these SE will experience an increasednumber of scattering events (due to that their associated energy isconsiderably lower than that of the PE) and these collisions generateeven more SE. This is significant, that the SE are scattered at angleslarger than 80° in arbitrary trajectories away from the primary beam.These electrons expose the resist material laterally. This is why the SEplays a major role in producing the nano structure.

FIG. 12 shows SEM images illustrating (a) Profile view of 6.22 nm lineson a 200 nm pitch (tilt 70°). (b) Profile view of 10.4 nm lines on a 100nm pitch (tilt 70°).

From the exposure doses presented in FIG. 12, it was possible tocalculate the number of electrons that were incident on each of theGW20-14 samples. To achieve this, the exposure parameters that producedthe nanostructures were; the step size between each exposure is 6.1 nmand the current and dwell time is 50 pA and 120.12 μS respectively. Thedose factor to fabricate the nanostructures with a pitch of 200 and 100nm was 6.2 and 9.95 respectively. Therefore, the number of electronsinserted to the GW20-14 materials was 23482 and 37686 respectively. FIG.13 shows a Monte Carlo simulation of the scattering trajectory crosssections when three nanostructures are fabricated.

It can be seen in FIGS. 7a and 7b that the simulation had producednanostructures with line widths of 7.5 and 11 nm. Comparing thesetheoretical results with experimental observations presented in FIG. 12,good agreement is found. Indeed the results of the model were increasedby a factor of 1.2 and 1.06, therefore, this equated that the model hasa discrepancy of approximately 1 nm.

FIG. 13 is a chart showing the internal electron scattering interactionsinside (a) GW20-14 that had a 7.5 nm nanostructure with a 200 nm pitchand had a dose of 6200 pC/cm, (b) GW20-14 that has a 10 nm nanostructurewith a 100 nm pitch and has a dose of 9950 pC/cm. Secondary electronsand backscattered electrons are indicated in Red and Blue respectively.

It was found that the Nickel Chromium ring like structured materialsproduce an increase in resolution of 6.22 nm while exhibiting aspectratios larger than 10:1 at an accelerating voltage of 30 KeV. Thisresult is significant as this is not possible using industry standardpolymeric type materials such as PMMA. This gave rise to exposure doseof 6200 pC/cm, which is slower by a factor of 8 when compared to theindustry stand PMMA. From this it can be ascertained that the exposuremethod was not contributed by the presence of SE, as the moleculeprohibits the creation of secondary electrons, due that its density was0.814 g/cm³ and its molecular weight was 16886.02 g/mol. This equates toapproximately 72 possible interactions that the primary electrons canexperience with the entire film in the z-direction. Therefore, theprimary electrons are responsible for the production of the pattern.This can be seen because the side wall profile appears to exhibitperpendicular angle of 90° when compared to the Silicon. This was shownto show strong agreement with the Monte Carlo simulation.

Applications of Technology

In view of the excellent resolution and aspect ratios obtainable inlithographic methods according to the invention, it is clear the resistcompositions and methods of the invention are ideal for producingimproved and potentially smaller integrated circuits. The skilled personis well able to adapt current IC production methods to incorporate oneor more lithographic steps using resist compositions of the invention.Alternatively, the present invention allows the skilled person toproduce a high-resolution lithographic mask, which may then in turn beused in the production of integrated circuits.

The present invention thus represents a significant contribution to afield which has long needed the advances in resolution, andpracticalities afforded by the present invention.

Example 6—Anti-Scattering Compounds with Appended Secondary ElectronGenerator(s) and/or Scattering Compound(s)

Though the eBeam resist compositions comprising the unadulteratinganti-scattering compounds described in the previous examples performexceptionally well, the following further experiments were performed inorder to establish whether the benefits of the unadulteratedanti-scattering compounds (e.g. extremely high resolution) could besubstantially maintained whilst increasing write speeds. To this end,various anti-scattering compounds were associated (by way of dativebonds) with either or both a secondary electron generator (such as oneof those recently developed by the same research team as per co-pendingapplication PCT/GB2015/050884) and/or a scattering compound, such as thealkene-based compounds now described.

The following procedures describe the fabrication of the relevant testedproducts.

Example 6.1

Synthesis of [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₅(O₂CC₅H₄N)] (Compound 1)

Compound [^(n)Pr₂NH₂][Cr₇Ni(μ-F)₈(O₂C^(t)Bu)₁₆] (15.0 g, 6.54 mmol),iso-nicotinic acid (2.48 g, 19.5 mmol) and n-propanol (300 mL) wererefluxed for 24 h with constant stirring. The resulting solution wascooled to room temperature and filtered. The solvent from the filtratewas removed under reduced pressure and extracted in diethyl ether (300mL). The obtained solution was filtered and the diethyl ether wasremoved under reduced pressure leaving a solid. This was extracted inpentane (200 mL), filtered and evaporated to dryness giving a greensolid, which was still a mixture of products. The mixture of compoundswere separated and purified by flash chromatography. First, toluene wasused as eluent, which allowed un-reacted starting material to be eluted,leaving the products of the reaction at the top of the column.Thereafter a mixture of petroleum ether/ethyl acetate (20/1) elution wasused to remove any remaining unreacted starting material. The solventratio was then gradually increased to 10/1, eluting a large single bandof 1. The solvent was removed under reduced pressure to obtain the titlecompound. 1 Yield: 4.89 g (32%). Elemental analysis (%) calcd forC₈₇H₁₅₅Cr₇F₈N₂NiO₃₂: Cr, 15.72, Ni, 2.53, C, 45.12, H, 6.75, N, 1.21.found: Cr, 15.97, Ni, 2.56, C, 44.90, H, 6.90, N, 1.19. ES-MS (sampledissolved in THF, run in MeOH): m/z=2338 [M+Na]⁺; 2316[M+H]⁺.

Coordination to 1Hg:

Compound 1 (100 mg, 0.04 mmol) was dissolved in hot acetone (10 mL). Asolution of mercury chloride (11.7 mg, 0.04 mmol) in acetone (2 mL) wasadded dropwise and the green solution was stirred at 50° C. for 1 hour.The solution was cooled to room temperature and concentrated. A greenmicrocrystalline powder was obtained. Elemental analysis (%) calcd forC₈₇H₁₅₅Cr₇F₈N₂NiO₃₂Hg: Cr, 14.46, Ni, 2.33, C, 41.53, H, 6.21, N, 1.11.found: Cr, 14.87, Ni, 2.67, C, 41.12, H, 5.88, N, 0.81.

Example 6.2

Synthesis of [^(n)Pr₂NH₂][Cr₂NiF₈(O₂C^(t)Bu)₁₄(O₂CC₅H₄N)₂] (Compound 2)

Compound [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₄(O₂CC₅H₄N)₂] (15.0 g, 6.54mmol), iso-nicotinic acid (2.48 g, 19.5 mmol) and n-propanol (300 mL)were refluxed for 24 h with constant stirring. The resulting solutionwas cooled to room temperature and filtered. The solvent from thefiltrate was removed under reduced pressure and extracted in diethylether (300 mL). The obtained solution was filtered and the diethyl etherwas removed under reduced pressure leaving a solid. This was extractedin pentane (200 mL), filtered and evaporated to dryness giving a greensolid, which was still a mixture of products. The mixture of compoundswere separated and purified by flash chromatography. First, toluene wasused as eluent, which allowed un-reacted starting material to be eluted.Thereafter a mixture of petroleum ether/ethyl acetate (20/1) elution wasused and then gradually worked up to a 5/1 mixture, eluting 2 asproduct. The solvent was removed under reduced pressure to obtain thetitle compound. Yield: 1.62 g (10%). Elemental analysis (%) calcd forC₈₈H₁₅₀Cr₇F₈N₃NiO₃₂: Cr, 15.57, Ni, 2.51, C, 45.25, H, 6.47, N, 1.80.found: Cr, 15.46, Ni, 2.38, C4, 5.56, H, 6.77, N, 1.82. ES-MS (sampledissolved in THF, run in MeOH): m/z=2359 [M+Na]⁺; 2337 [M+H]⁺.

Coordination to 2Hg:

Compound 2 (100 mg, 0.04 mmol) was dissolved in hot acetone (10 mL). Asolution of mercury chloride (23.1 mg, 0.08 mmol) in acetone (2 mL) wasadded dropwise and the green solution was stirred at 50° C. for 1 hour.The solution was cooled to room temperature and concentrated. A greenmicrocrystalline powder was obtained. Elemental analysis (%) calcd forC₈₈H₁₅₀Cr₇F₈N₃NiO₃₂Hg₂: Cr 13.29, Ni, 2.14, C, 38.61, H, 5.52, N, 1.53.found: Cr, 13.60, Ni, 1.09, C, 38.19, H, 6.01, N, 1.02.

Example 6.3

Synthesis of [^(n)Pr₂NH₂][Cr₂NiF₈(O₂C^(t)Bu)₁₂(O₂CC₅H₄N)₄] (Compound 3)

Compound [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₂(O₂CC₅H₄N)₄] (15.0 g, 6.54mmol), iso-nicotinic acid (2.48 g, 19.5 mmol) and n-propanol (300 mL)were refluxed for 24 h with constant stirring. The resulting solutionwas cooled to room temperature and filtered. The solvent from thefiltrate was removed under reduced pressure and extracted in diethylether (300 mL). The obtained solution was filtered and the diethyl etherwas removed under reduced pressure leaving a solid. This was extractedin pentane (200 mL), filtered and evaporated to dryness giving a greensolid, which was still a mixture of products. The mixture of compoundswere separated and purified by flash chromatography. First, toluene wasused as eluent, which allowed un-reacted starting material to be eluted.Thereafter, acetone was used to elute 3 as product. The solvent wasremoved under reduced pressure to obtain the title compound. Yield: 1.22g (8%). Elemental analysis (%) calcd for C₉₀H₁₄₀Cr₇F₈N₅NiO₃₂: C, 45.44,H, 5.93, N, 2.94. found: C, 45.63, H, 5.87, N, 3.11. ES-MS (sampledissolved in THF, run in MeOH): m/z=2399 [M+Na]⁺; 2379 [M+H]⁺.

Coordination to 4Hg:

Compound 3 (100 mg, 0.02 mmol) was dissolved in hot acetone (10 mL). Asolution of mercury chloride (21.6 mg, 0.08 mmol) in acetone (2 mL) wasadded dropwise and the green solution was stirred at 50° C. for 1 hour.The solution was cooled to room temperature and concentrated. A greenmicrocrystalline powder was obtained. Elemental analysis (%) calcd forC₉₀H₁₄₀Cr₇F₈N₅NiO₃₂Hg₄: Cr, 11.44, Ni, 1.85, C, 33.98, H, 4.44, N, 2.20.found: Cr, 11.81, Ni, 1.56, C, 34.29, H, 4.11, N, 1.83.

Example 6.4

Synthesis of [C₆H₁₁NH₂][Cr₇NiF₈(O₂CC₂H)₁₆] (Compound 4)

Pivalic acid (20.0 g, 195 mmol), diallylamine (0.55 g, 5.6 mmol), andchromium(III) fluoride tetrahydrate (6.7 g, 39 mmol) were heated at 140°C. with stirring in a Teflon flask for 0.5 h, then nickel(II) carbonatehydroxide tetrahydrate (0.98 g, 1.67 mmol) was added. After 1 h thetemperature of the reaction was increased to 160° C. for 24 h. The flaskwas cooled to room temperature, and then acetone (35 mL) was added whilestirring. The green microcrystalline product was collected byfiltration, washed with a large quantity of acetone, dried in air. Flashchromatography with toluene as eluent afforded the desired compound 4 asgreen crystalline solid. Yield: 7.7 g (60%). Elemental analysis (%)calcd for C₈₆H₁₅₆Cr₇F₈NNiO₃₂: Cr, 15.89, Ni, 2.56, C, 45.09, H, 6.86, N,0.61. found: Cr, 15.43, Ni, 2.32, C, 45.65, H, 6.81, N, 1.11. ES-MS(sample dissolved in THF, run in MeOH): m/z=2313 [M+Na]⁺; 2291 [M+H]⁺.

Example 6.5—Synthesis of N-allylhexa-2,4-dien-1-amine

To a solution of 2,4-hexanedienal (1.15 mL, 10.4 mmol) in 30 mLmethanol, allylamine (0.78 mL, 13.6 mmol) in 5 mL methanol was added andthe reaction mixture was stirred overnight under nitrogen atmosphere.Then an excess of NaBH₄ was added (5 equivalents) at 0° C. and reactionmixture stirred for 12 h under nitrogen atmosphere at room temperature.The reaction was quenched with water and the solvents evaporated underreduced pressure. The residue was extracted with chloroform and washedwith water. The organic extract was dried over anhydrous magnesiumsulphate and evaporated under reduced pressure and the compound wasobtained as a light yellow oil in 90% yield (1.28 g). ES-MS (sampledissolved in MeOH, run in MeOH): m/z=138 [M+H]⁺. NMR (400 MHz, 293K,CDCl₃): δ=1.7 (d, 3H), 3.22 (d, 4H), 5.08-5.17 (m, 2H), 5.72-5.76 (m,3H), 5.8-6.02 (m, 2H).

Synthesis of [C₉H₁₅NH₂][Cr₇NiF₈(O₂CC₂H₅)₁₆] (Compound 5)

Pivalic acid (20.0 g, 195 mmol), N-allylhexa-2,4-dien-1-amine (0.65 g,4.7 mmol), and chromium(III) fluoride tetrahydrate (6.0 g, 33.2 mmol)were heated at 140° C. with stirring in a Teflon flask for 0.5 h, thennickel(II) carbonate hydroxide tetrahydrate (0.83 g, 1.42 mmol) wasadded. After 1 h the temperature of the reaction was increased to 160°C. for 24 h. The flask was cooled to room temperature, and then acetone(35 mL) was added while stirring. The green microcrystalline product wascollected by filtration, washed with a large quantity of acetone, driedin air. Flash chromatography with toluene as eluent afforded the desiredcompound 5 as green crystalline solid. Yield: 2.7 g (25%). Elementalanalysis (%) calcd for C₈₉H₁₆₀Cr₇F₈NNiO₃₂: Cr, 15.62, Ni, 2.52, C,45.86, H, 6.92, N, 0.60. found: Cr, 15.13, Ni, 2.39, C, 45.10, H, 6.48,N, 0.55. ES-MS (sample dissolved in THF, run in MeOH): m/z=2353 [M+Na]⁺;2331 [M+H]⁺.

Example 6.6—Synthesis of bis(2-(hepta-1,6-dien-4-yloxy)ethyl)amine

To a solution of NaH (0.83 g, 5 equiv) in anhydrous DMF (10 mL), thedienol (1 g, 8.9 mmol, 2 equiv) was added dropwise at 0° C. The mixturewas stirred for 15 min, and then bis(2-chloroethyl)amine hydrochloride(0.78 g, 1 equiv) was added. The mixture was allowed to warm to r.t. andstirred overnight. Excess NaH was quenched by addition of ice at 0° C.and the mixture was stirred for 10 min. The mixture was poured into H₂O,extracted with ethyl acetate (3×50 mL). The combined organic layers werewashed with H₂O and brine solution, dried (anhydrous Na₂SO₄), andconcentrated under reduced pressure. The residue was purified by flashchromatography (silica gel) to furnish the desired compound in 60% yield(0.7 g). ES-MS (sample dissolved in MeOH, run in MeOH): m/z=294 [M+H]⁺.NMR (400 MHz, 293K, CDCl₃): δ=2.15-2.32 (m, 8H), 2.80 (t, 4H), 3.62-3.70(m, 2H), 3.76-3.89 (m, 4H), 5.13-5.34 (m, 8H), 5.85-6.03 (m, 4H).

Synthesis of [C₁₈H₃₁NO₂][Cr₇NiF₈(O₂CC₂H₅)₁₆] (Compound 6)

Pivalic acid (20.0 g, 195 mmol),bis(2-(hepta-1,6-dien-4-yloxy)ethyl)amine (0.5 g, 1.7 mmol), andchromium(III) fluoride tetrahydrate (2.1 g, 11.9 mmol) were heated at140° C. with stirring in a Teflon flask for 0.5 h, then nickel(II)carbonate hydroxide tetrahydrate (0.31 g, 0.53 mmol) was added. After 1h the temperature of the reaction was increased to 150° C. for 25 h. Theflask was cooled to room temperature, and then acetone (35 mL) was addedwhile stirring. The green microcrystalline product was collected byfiltration, washed with a large quantity of acetone, dried in air. Flashchromatography with toluene as eluent afforded the desired compound 6 asgreen crystalline solid. Yield: 0.2 g (5%). Elemental analysis (%) calcdfor C₉₃H₁₇₆Cr₇F₈NNiO₃₄: Cr, 14.64, Ni, 2.36, C, 47.33, H, 7.13, N, 0.56.found: Cr, 14.99, Ni, 2.17, C, 47.60, H, 6.67, N, 0.73. ES-MS (sampledissolved in THF, run in MeOH): m/z=2509 [M+Na]⁺; 2487[M+H]⁺.

Example 6.7

Synthesis of [C₆H₁₁NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₄(O₂CC₅H₄N₂)₂] (Compound 7)

Compound [C₆H₁₁NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₄(O₂CC₅H₄N)₂] (7.5 g, 3.27 mmol),iso-nicotinic acid (1.2 g, 9.75 mmol) and n-propanol (150 mL) wererefluxed for 24 h with constant stirring. The resulting solution wascooled to room temperature and filtered. The solvent from the filtratewas removed under reduced pressure and extracted in diethyl ether (100mL). The obtained solution was filtered and the diethyl ether wasremoved under reduced pressure leaving a green solid. First, toluene wasused as solvent, which allowed un-reacted starting material to beeluted, leaving the products of the reaction at the top of the column.Thereafter a mixture of petroleum ether:ethyl acetate (20/1) elution wasused to remove any remaining unreacted starting material. The solventratio was then gradually worked up to a 5/1 mixture, eluting 7 asproduct. The solvent was removed under reduced pressure to obtain thetitle compound. Yield: 0.79 g (10%). Elemental analysis (%) calcd forC₈₈H₁₄₆Cr₇F₈N₃NiO₃₂: Cr, 15.60, Ni, 2.52, C, 45.31, H, 6.31, N, 1.80.found: Cr, 15.83, Ni, 2.11, C, 46.33, H, 5.80, N, 2.11. ES-MS (sampledissolved in THF, run in MeOH): m/z=2355 [M+Na]⁺; 2333 [M+H]⁺.

Coordination to 2Hg:

Compound 7 (100 mg, 0.04 mmol) was dissolved in hot acetone (10 mL). Asolution of mercury chloride (23.1 mg, 0.08 mmol) in acetone (2 mL) wasadded dropwise and the green solution was stirred at 50° C. for 1 hour.The solution was cooled to room temperature and concentrated. A greenmicrocrystalline powder was obtained. Elemental analysis (%) calcd forC₈₈H₁₄₂Cr₇F₈N₃NiO₃₂Hg₂: Cr, 13.33, Ni, 2.15, C, 38.72, H, 5.24, N, 1.54.found: Cr, 13.71, Ni, 2.01, C, 38.39, H, 5.72, N, 1.09.

Example 6.8—Synthesis of methyl 3,5-di(pyridin-4-yl)benzoate

A mixture of methyl 3,5-dibromobenzoate (1.5 g, 5.1 mmol),4-pyridylboronic acid pinacol ester (3.5 g, 16.9 mmol), Pd(PPh₃)₄(0.6g), and K₃PO₄ (8 g, 40.0 mmol) in dioxane (120 mL) was refluxed for 3 dunder an argon atmosphere. The reaction mixture was treated with waterand the products were extracted with CHCl₃, and washed with water. Theorganic extract was dried over anhydrous magnesium sulphate andevaporated under reduced pressure. The result was purified by columnflash chromatography on silica gel (CHCl₃/MeOH (10/1)) to give the titlecompound as a pale yellow solid. Yield: 0.7 g (50%). ES-MS (sampledissolved in THF, run in MeOH): m/z=291 [M+H]⁺. NMR (500 MHz, 293K,CDCl₃): δ=3.9 (s, 3H), 7.6 (s, 2H), 8.1 (s, 1H), 8.4 (d, 4H), 8.7 (d,4H).

Synthesis of 3,5-di(pyridin-4-yl)benzoic acid

A solution of methyl 3,5-di(pyridin-4-yl)benzoate (0.7 g, 2.41 mmol) ina mixture of MeOH/THF/H₂O (30/20/6 mL) LiOH (0.11 g, 2 equiv) was added.The reaction mixture was stirred at room temperature for 24 h. MeOH andTHF were removed in vacuum, and the residue was acidified with 1Maqueous HCl to pH 5. The resulting solid was isolated by filtration,washed with cold water (10 mL), and dried in vacuum. The filtrate wasconcentrated in vacuum and additionally acidified with 1 M aqueous HClto pH 5. Additional solid precipitated which was filtered, washed withcold water (3 mL) and dried in vacuum to give the product as whitesolid. Yield: 0.5 g (71%). ES-MS (sample dissolved in THF, run in MeOH):m/z=277 [M+H]⁺. NMR (400 MHz, 293K, DMSO): δ=7.7 (s, 2H), 7.9 (s, 1H),8.1 (d, 4H), 8.5 (d, 4H), 12.9 (s, 1H).

Synthesis of [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₅(O₂C(C₆H₄)₂OH)]

An excess of 4′-hydroxy-4-biphenylcarboxylic acid (1.71 g, 8.0 mmol) wasreacted with [^(n)Pr₂NH₂][Cr₇Ni(μ-F)₈(O₂C^(t)Bu)₁₆] (6.92 g, 3.0 mmol)in toluene (25 mL), dimethylformamide (25 mL) and 1,2-dichlorobenzene(75 mL). The solution was heated with constant stirring at 150° C. for12 h in a round-bottomed flask. Solvent was removed under reducedpressure and the resulting residue was purified by columnchromatography. First toluene, followed by 60/1 toluene/ethyl acetatewas used, which allowed un-reacted [^(n)Pr₂NH₂][Cr₇Ni(μ-F)₈(O₂C^(t)Bu)₁]to be eluted, leaving the products of the reaction at the top of thecolumn. Thereafter 40/1 toluene/ethyl acetate was used, eluting theproduct. The solvent was removed under reduced pressure and X-rayquality crystals were obtained from recrystallization from Et₂O/MeCN(2.89 g, 40%). ESI-MS (m/z): 2429 [M+Na]⁺; 2407 [M+H]⁺. Elementalanalysis (%) calcd for C₉₄H₁₆₀Cr₇F₈NNiO₃₃: Cr, 15.12, Ni, 2.44, C,46.91, H, 6.70, N, 0.58. found: Cr, 15.17, Ni, 2.47, C, 47.05, H, 6.78,N, 0.60.

Synthesis of[^(n)Pr₂NH₂][Cr₂NiF₈(O₂C^(t)Bu)₁₅(O₂C(C₆H₄)₂O₂C(C₆H₃)(C₆H₄N)₂)]

A mixture of [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₅(O₂C(C₆H₄)₂OH)] (1 g, 0.4mmol), 3,5-di(pyridin-4-yl)benzoic acid (0.11 g, 0.4 mmol),dicyclohexylcarbodiimide (0.26 g, 1.26 mmol), 4-dimethylamino pyridine(0.14 g, 1.26 mmol) in dry THF (50 mL) was stirred for 48 h at roomtemperature under argon atmosphere. The reaction mixture was filtered toremove the dicyclohexylurea formed. The solvent was removed underreduced pressure leaving a solid. The solid was extracted in hexane (200mL), the solution was filtered and evaporated to dryness giving a greensolid, which was separated and purified by flash chromatography usingtoluene and then toluene/ethyl acetate as eluents to give the titlecompound as a green solid. Yield: 0.2 g (20%). Elemental analysis (%)calcd for C₁₁₁H₁₇₀Cr₇F₈N₃NiO₃₄: Cr, 13.66, Ni, 2.20, C, 50.03, H, 6.43,N, 1.58. found: Cr, 13.43, Ni, 2.12, C, 50.31, H, 6.90, N, 1.19. ES-MS(sample dissolved in THF, run in MeOH): m/z=2688 [M+Na]; 2666 [M]⁺.

Synthesis of[{[^(n)Pr₂NH₂][Cr₇Ni(μ-F)₈(O₂C^(t)Bu)₁₅(O₂CC₃₃H₁₉O₂N₂)]}₂₄Pd₁₂(BF₄)₂₄]8

Compound [^(n)Pr₂NH₂][Cr₇NiF₈(O₂C^(t)Bu)₁₅(O₂C(C₆H₄)₂O₂C(C₆H₃)(C₆H₄N)₂)](0.07 g, 0.026 mmol) was dissolved in hot acetone (2 mL). A solution ofPd(BF₄)₂.4CH₃CN (0.004 g, 0.0013 mmol) in acetone (2 mL) was addeddropwise and the green solution was stirred at 50° C. for 12 hours. Thesolution was concentrated to obtain a green powder. Elemental analysis(%) calcd for C₂₆₅₄H₄₀₈₀B₂₄Cr₁₅₈F₂₈₈N₇₂Ni₂₄O₈₁₆Pd₁₂: Cr, 12.97, Ni,2.09, C, 47.53, H, 6.11, N, 1.50. found: Cr, 12.42, Ni, 1.98, C, 48.39,H, 6.50, N, 1.10.

Example 6.9—Nanocomposite Material which Comprises of Fujita Cage with24 Satellite Cr₇Ni Rings Attached and DiAllylamine, where theDiallylamine is not Attached to the Cage

The relevant formulation is shown in Table 6 below, and is formed bymixing 30 mg of the Fujita Cage with 24 satellite Cr7Ni rings attachedthereto with 2 g of Tert Butyl Methyl Ether. 6 mg of Diallylamine isthen introduced into the mix.

Example 6.10—Nanocomposite Material which Comprises of Fujita Cage with24 Satellite Cr₇Ni Rings Attached and Trans Trans Farnesyl Bromide,where the Trans Trans Farnesyl Bromide is not Attached to the Cage

The relevant formulation is shown in Table 6 below, and is formed bymixing 30 mg of the Fujita Cage with 24 satellite Cr7Ni rings attachedthereto with 2 g of Tert Butyl Methyl Ether. 6 mg of trans transfarnesyl bromide is then introduced into the mix.

Example 6.11—Nanocomposite Material which Comprises of Fujita Cage with24 Satellite Cr₇Ni Rings Attached and Pentraerythritol Tetraacrylate,where the Pentraerythritol Tetraacrylate is not Attached to the Cage

The relevant formulation is shown in Table 6 below, and is formed bymixing 30 mg of the Fujita Cage with 24 satellite Cr7Ni rings attachedthereto with 2 g of Tert Butyl Methyl Ether. 6 mg of Pentraerythritoltetraacrylate is then introduced into the mix.

Example 6A—Production of eBeam Resist Compositions

eBeam resist formulations were prepared using the anti-scatteringcompounds (with or without appended secondary electron generator(s)and/or scattering compounds) as explained below.

Resist formulations containing Cr₇Ni Ring molecule and HgCl₂ wereprepared according to the formulations shown in Table 3:

Table 3 Shows the Resist Formulations that have HgCl₂ Attached to aCr₇Ni Ring.

Cr₇Ni Ring + Cr₇Ni Ring + Cr₇Ni Ring + Tert Butyl Methyl 1HgCl_(2 (Ex)6.1) 2HgCl_(2 (Ex) 6.2) 4HgCl_(2 (Ex) 6.3) Ether (tBME) 15 mg — — 2 g —15 mg — 2 g — — 15 mg 2 g

Table 4 shows the resist formulations that incorporate Alkene groupsattached inside the Cr₇Ni Ring. The relevant alkene structures are alsoillustrated below.

Table 4 Shows the Resist Formulations that have Alkene MoleculesAttached Inside a Cr₇Ni Ring.

Cr₇Ni Ring + Cr₇Ni Ring + Cr₇Ni Ring + 4 Tert Butyl Methyl DiAllylamineTriAllylamine Alkene groups Ether (tBME) 15 mg — — 2 g — 15 mg — 2 g — —15 mg 2 g

Table 5 shows resist formulations of two HgCl₂ attached to the Cr₇NiRing molecule where the Cr₇Ni Ring had a DiAllylamine attached inside it

Table 5 Shows the Resist Formulations that have Cr₇Ni Ring and TwoEquivalents of HgCl₂ with DiAllylamine Attached Inside it.

Cr₇Ni Ring (DiAllylamine) + Cr₇Ni Ring + Cr₇Ni Ring + Tert Butyl Methyl2HgCl₂ 2HgCl₂ 4HgCl₂ Ether (tBME) 15 mg — — 2 g

Table 6 shows resist formulations containing “Fujita cage” nanocompositeformulations. A nanocomposite material that uses the Fujita cage with 24satellite Cr₇Ni rings that orbit it was fabricated and the nanocompositeresist formulation is given table 6. The other molecules that were mixedwith the Fujita cage had 2, 3 and 8 Alkene groups associated with theirmolecular structure. This was done in an attempt to potentially increasewrite speed. The alkene structures are shown below.

TABLE 6 “Fujita cage” nanocomposite resist formulations Fujita Cage withTert Butyl Trans trans 24 satellite Methyl Ether Diallyl- farnesylPentraerythritol CrNi rings (tBME) amine Bromide tetraacrylate 30 mg 2 g— — — 30 mg 2 g 6 mg — — (20%) 30 mg 2 g — 6 mg — (20%) 30 mg 2 g — — 6mg (20%)

Example 6B—Preparation of Wafers for Testing

Using the compositions of Example 6A, silicon wafers were prepared inorder to compare the performance of the resist compositions of Example6A.

The formulations of Example 6A were spun onto 10 mm×10 mm siliconsubstrates. The resist was spun using a spin cycle of 8000 rpm for 30seconds, which was followed by a soft-bake at 100° C. for 2 minutes,allowing the cast solvent to evaporate. The resist film resulted with athickness of 100 nm. The exposure clearing doses of each resist materialwas determined from a ten 1-dimensional matrix of a single pixel line by20 μm long, therefore the width of the line was the width of theelectron beam. The first 1-dimensional matrix had each single pixel lineseparated by a pitch of 100 nm. These were exposed with a dose scalefrom 1 to 20.9 pC/cm in incremental steps of 0.1 pC/cm, while, thesecond to the tenth 1-dimensional matrices had a pitches of 90 to 50 nmin decremental pitches of 5 nm.

All resists were then exposed using a FEI Sirion Scanning ElectronMicroscope (SEM). The exposed pattern was written using an accelerationvoltage of 30 KeV, a probe current of 50 pA, the dwell time was 12 μSand the step size was 12 nm. From these exposure parameters, the basedose was calculated to be 500 pC/cm. Each pattern was exposed using awrite field of 100 μm. Each material was developed using a solution ofHexane, for 30 s followed by an N₂ blow dry.

Result and Discussion for Example 6

The aforementioned compounds/compositions were tested in their capacityas eBeam resists, in the same or similar manner as per theantiscattering compounds/resists described in the Examples precedingExample 6. In particular, the eBeam resist compositions (which may beconsidered compositions by virtue of the inclusion of multiplecompounds, despite the fact that the compounds may associate as part ofthe same complex) of Example 6 were assessed in terms of feature/writewidth (which is a measure of resolution and focusing) and also therequired exposure dose (which is an indication of write speed).

Table 7 below summarises the tests carried out in respect of each ofExample 6.1-6.11 by reference to relevant Figures and exposure dosevalues. FIGS. 14.1-14.11 are SEM images showing various lines writtenusing eBeam in the various eBeam resist compositions.

TABLE 7 Test Data for Example 6.1-6.11 Feature Clearing FIG. widthExposure Dose Ex eBeam resist description No. (nm) (pC/cm) 6.1 Cr₇Niring with 1 HgCl₂ present 14.1 12.2 10600 6.2 Cr₇Ni ring with 2 HgCl₂present 14.2 13.9 2200 6.3 Cr₇Ni ring with 4 HgCl₂ present 14.3 13.91400 6.4 Cr₇Ni ring with a DiAllylamine attached 14.4 15.7 15000 6.5Cr₇Ni ring with a TriAllylamine attached 14.5 15.7 10200 6.6 Cr₇Ni ringwith an organic with 4 Alkene groups 14.6 17.4 7200 6.7 Cr₇Ni ring witha DiAllylamine attached in the middle and 2 14.7 7.5 1760 HgCl₂ present6.8 Fujita Cage with 24 satellite Cr₇Ni rings attached 14.8 6.9 5000 6.9Nanocomposite material which comprises of Fujita Cage with 24 14.9 8.72600 satellite Cr₇Ni rings attached and DiAllylamine. The DiAllylamineis not attached. DiAllylamine has 2 Alkene groups. 6.10 Nanocompositematerial which comprises of Fujita Cage with 24 14.10 6.9 3400 satelliteCr₇Ni rings attached and trans trans farnesyl Bromide. The trans transfarnesyl Bromide is not attached. Trans trans farnesyl Bromide has 3Alkene groups. 6.11 Nanocomposite material which comprises of FujitaCage with 24 14.11 6.9 1150 satellite Cr₇Ni rings attached andPentraerythritol tetraacrylate. The Pentraerythritol tetraacrylate isnot attached. Pentraerythritol tetraacrylate has 8 Alkene groups.

These results indicate that a synergistic effect can be achieved throughcombining antiscattering compounds with either or both a secondaryelectron generator and/or a scattering compound. Such a synergisticeffect permits write speeds to be increased without significantlycompromising the resolution.

REFERENCES General Reviews

-   M. Affronte, S. Carretta, G. A. Timco and R. E. P. Winpenny, “A Ring    Cycle: Studies of Heterometallic Wheels”, Chem. Commun., 2007,    1789-1797.-   G. A. Timco, T. B. Faust, F. Tuna and R. E. P. Winpenny, “Linking    Rings for Quantum Information Processing and Amusement”, Chem. Soc.    Rev. 2011, 40, 3067-3075.-   G. A. Timco, E. J. L. McInnes and R. E. P. Winpenny, “Physical    Studies of Heterometallic Rings: An Ideal System for Studying    Magnetically-Coupled Systems”, Chem. Soc. Rev. 2013, 42, 1796-1806.    References Relevant to Antiscattering Compounds Comprising a Primary    Metal Complex of Formula [M¹ _(x)M²    _(y)(monoLIG¹)_(m1)(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]-   F. K. Larsen, E. J. L. McInnes, H. El Mkami, J. Overgaard, S.    Piligkos, G. Rajaraman, E. Rentschler, A. A. Smith, G. M. Smith, V.    Boote, M. Jennings, G. A. Timco and R. E. P. Winpenny, “Synthesis    and Characterisation of Heterometallic {Cr₇M} Wheels”, Angew. Chem.    Int. Ed. 2003, 42, 101-105.-   J. van Slageren, R. Sessoli, D. Gatteschi, A. A. Smith, M.    Helliwell, R. E. P. Winpenny, A. Cornia, A.-L. Barra, A. G. M.    Jansen, G. A. Timco and E. Rentschler, “Magnetic Anisotropy of the    Antiferromagnetic Ring [Cr₈F₈Piv₁₆]: A Cantilever Torque    Magnetometry and High-Frequency EPR Study”, Chem. Eur. J., 2002, 8,    277-285.-   R. H. Laye, F. K. Larsen, J. Overgaard, C. A. Muryn, E. J. L.    McInnes, E. Rentschler, V. Sanchez, H. U. Güdel, O. Waldmann, G. A.    Timco and R. E. P. Winpenny, “A Family of Heterometallic Wheels    Containing Potentially Fourteen Hundred Siblings”, Chem. Commun.    2005, 1125-1127.-   M. Affronte, I. Casson, M. Evangelisti, A. Candini, S.    Carretta, C. A. Muryn, S. J. Teat, G. A. Timco, W. Wernsdorfer    and R. E. P. Winpenny, “Linking Rings Through Diamines and Clusters:    Exploring Synthetic Methods for Making Magnetic Quantum Gates”,    Angew. Chem. Int. Ed., 2005, 44, 6496-6500.-   C.-F. Lee, D. A. Leigh, R. G. Pritchard, D. Schultz, S. J.    Teat, G. A. Timco and R. E. P. Winpenny, “Hybrid organic-inorganic    rotaxanes and molecular shuttles”, Nature, 2009, 458, 314-318.-   G. A. Timco, S. Carretta, F. Troiani, F. Tuna, R. G.    Pritchard, E. J. L. McInnes, A. Ghirri, A. Candini, P. Santini, G.    Amoretti, M. Affronte and R. E. P. Winpenny, “Engineering Coupling    Between Molecular Spin Qubits By Coordination Chemistry” Nature    Nanotechnology, 2009, 4, 173-178.-   T. B. Faust, P. G. Heath, C. A. Muryn, G. A. Timco and R. E. P.    Winpenny, “Cesium ion sequestration by a fluoro-metallocrown    [16]-MC-8”, Chem. Commun., 2010, 46, 6258-6260.-   B. Ballesteros, T. B. Faust, C.-F. Lee, D. A. Leigh, C. A.    Muryn, R. G. Pritchard, D. Schultz, S. J. Teat, G. A. Timco    and R. E. P. Winpenny, “Synthesis, Structure and Dynamic Properties    of Hybrid Organic-Inorganic Rotaxanes”, J. Amer. Chem. Soc. 2010,    132, 15435-15444.-   M. L. Baker, S. Piligkos, A. Bianchi, S. Carretta, D.    Collison, J. J. W. McDouall, E. J. L. McInnes, H. Mutka, G. A.    Timco, F. Tuna, P. Vadivelu, H. Weihe, H. U. Güdel and R. E. P.    Winpenny, “Modification of the magnetic properties of a    heterometallic wheel by inclusion of a Jahn-Teller distorted Cu(II)    ion”, Dalton Trans., 2011, 40, 8533-8539.-   C. J. Wedge, R. E. George, G. A. Timco, F. Tuna, S. Rigby, E. J. L.    McInnes, R. E. P. Winpenny, S. J. Blundell and A. Ardavan, “Chemical    engineering of molecular qubits”, Phys. Rev. Lett., 2012, 108,    107204.-   H. Rath, G. A. Timco, V. Corradini, A. Ghirri, U. del Pennino, A.    Fernandez, R. G. Pritchard, C. A. Muryn, M. Affronte and R. E. P.    Winpenny, “Studies of Hybrid Organic-Inorganic [2] and [3] Rotaxanes    Bound to Au Surfaces”, Chem. Commun., 2013, 4, 3404-3406.-   G. F. S. Whitehead, B. Cross, L. Carthy, V. A. Milway, H. Rath, A.    Fernandez, S. L. Heath, C. A. Muryn, R. G. Pritchard, S. J.    Teat, G. A. Timco and R. E. P. Winpenny, “Rings and threads as    linkers in metal-organic frameworks and poly-rotaxanes”, Chem.    Commun., 2013, 49, 7195-7197.-   G. F. S. Whitehead, F. Moro, G. A. Timco, W. Wernsdorfer, S. J. Teat    and R. E. P. Winpenny, “A Ring of Rings and Other Multicomponent    Assemblies of Clusters”, Angew. Chem. Int. Ed., 2013, 52, 9932-9935.-   G. F. S. Whitehead, J. Ferrando-Soria, L. G. Christie, N. F.    Chilton, G. A. Timco, F. Moro and R. E. P. Winpenny, “The Acid Test:    the chemistry of carboxylic acid functionalised {Cr₇Ni} rings,”    Chem. Sci., 2014, 5, 235-239.    References Relevant to Antiscattering Compounds Comprising a Primary    Metal Complex of Formula [M¹ _(8-y)M²    _(y)F₃(O₂CR_(B1))₁₅(Gluc-NH—R_(O1))]-   G. A. Timco, E. J. L. McInnes, R. G. Pritchard, F. Tuna and R. E. P.    Winpenny, “Heterometallic Rings Made from Chromium Stick Together    Easily”, Angew. Chem. Int. Ed. 2008, 47, 9681-9684.-   T. B. Faust, V. Bellini, A. Candini, S. Carretta, G. Lorusso, D. R.    Allan, L. Carthy, D. Collison, R. J. Docherty, J. Kenyon, J.    Machin, E. J. L. McInnes, C. A. Muryn, H. Nowell, R. G.    Pritchard, S. J. Teat, G. A. Timco, F. Tuna, G. F. S. Whitehead, W.    Wernsdorfer, M. Affronte and R. E. P. Winpenny, “Chemical control of    spin propagation between heterometallic rings”, Chem. Eur. J. 2011,    17, 14020-14030.-   T. B. Faust, F. Tuna, G. A. Timco, M. Affronte, V. Bellini, W.    Wernsdorfer and R. E. P. Winpenny “Controlling magnetic    communication through aromatic bridges by variation in torsion    angle”, Dalton Trans., 2012, 41, 13626-13631.-   E. Garlatti, M. A. Albring, M. L. Baker, R. J. Docherty, V. Garcia    Sakai, H. Mutka, T. Guidi, G. F. S. Whitehead, R. G.    Pritchard, G. A. Timco, F. Tuna, G. Amoretti, S. Carretta, P.    Santini, G. Lorusso, M. Affronte, E. J. L. McInnes, D. Collison    and R. E. P. Winpenny, “A detailed study of the magnetism of chiral    {Cr₇M} rings: an investigation into parameterization and    transferability of parameters” . . . accepted for J. Amer. Chem.    Soc.

References Relevant to Other Potential Antiscattering Compounds

-   F. K. Larsen, J. Overgaard, S. Parsons, E. Rentschler, G. A.    Timco, A. A. Smith and R. E. P. Winpenny, “Horseshoes, Rings and    Distorted Rings: Studies of Reactions of Chromium-Fluoride Wheels”,    Angew. Chem. Int. Ed., 2003, 42, 5978-5981.-   O. Cador, D. Gatteschi, R. Sessoli, F. K. Larsen, J. Overgaard,    A.-L. Barra, S. J. Teat, G. A. Timco and R. E. P. Winpenny, “The    Magnetic Mobius Strip: Synthesis, Structure and First Magnetic    Studies of Odd-Numbered Anti-Ferromagnetically Coupled Wheels”,    Angew. Chem. Int. Ed. 2004, 43, 5196-5200.-   S. L. Heath, R. H. Laye, C. A. Muryn, R. Sessoli, R. Shaw, S. J.    Teat, G. A. Timco and R. E. P. Winpenny, “Ringing The Changes:    Templating Open and Closed-Chain Structures About Metal-Macrocycle    Complexes”, Angew. Chem. Int. Ed. 2004, 43, 6132-6135.-   G. A. Timco, A. S. Batsanov, F. K. Larsen, C. A. Muryn, J.    Overgaard, S. J. Teat and R. E. P. Winpenny, “Influencing The    Nuclearity and Constitution of Heterometallic Rings Via Templates”,    Chem. Commun. 2005, 3649-3651.-   M. Shanmugam, L. P. Englehardt, F. K. Larsen, M. Luban, C. A.    Muryn, E. J. L. McInnes, J. Overgaard, E. Rentschler, G. A. Timco    and R. E. P. Winpenny, “Synthesis and Studies of a Cyclic    Dodecanuclear {Cr₁₀Cu₂} Complex”, Chem. Eur. J., 2006, 12,    8267-8275.-   L. P. Engelhardt, C. A. Muryn, R. G. Pritchard, G. A. Timco, F. Tuna    and R. E. P. Winpenny, “Octa-, Deca-, Trideca- and Tetradeca-nuclear    Heterometallic Cyclic Chromium-Copper Cages”, Angew. Chem. Int. Ed.    2008, 47, 924-927.-   M. Rancan, G. N. Newton, C. A. Muryn, R. G. Pritchard, G. A.    Timco, L. Cronin and R. E. P. Winpenny, “Chemistry and    supramolecular chemistry of chromium(III) horseshoes”, Chem. Commun.    2008, 1560-1562.-   A. B. Boeer, D. Collison, C. A. Muryn, G. A. Timco, F. Tuna    and R. E. P. Winpenny, “Linkage Isomerism and Spin Frustration in    Heterometallic Rings: Synthesis, Structural Characterisation and    Magnetic and EPR Spectroscopic Studies of Cr7Ni, Cr6Ni2 and Cr7Ni2    Rings Templated About Imidazolium Cations”, Chem. Eur. J. 2009, 15,    13150-13160.-   M. L. Baker, A. Bianchi, S. Carretta, D. Collison, R.    Docherty, E. J. L. McInnes, A. McRobbie, C. A. Muryn, H. Mutka, S.    Piligkos, M. Rancan, P. Santini, G. A. Timco, P. L. W.    Tregenna-Piggott, F. Tuna, H. U. Güdel and R. E. P. Winpenny,    “Varying Spin State Composition by the Choice of Capping Ligand in A    Family of Molecular Chains: Detailed Analysis of Magnetic Properties    of Chromium(III) Horseshoes”, Dalton Trans., 2011, 40, 2725-2734.-   A. McRobbie, A. R. Sarwar, S. Yeninas, H. Nowell, M. L. Baker, D.    Allan, M. Luban, C. A. Muryn, R. G. Pritchard, R. Prozorov, G. A.    Timco, F. Tuna, G. F. S. Whitehead and R. E. P. Winpenny, “Chromium    Chains as Polydentate Fluoride Ligands for Lanthanides”, Chem.    Commun. 2011, 47, 6251-6253.-   M. L. Baker, G. A. Timco, S. Piligkos, J. Mathieson, H. Mutka, F.    Tuna, P. Kozlowski, M. Antkowiak, T. Guidi, T. Gupta, H. Rath, R. J.    Woolfson, G. Kamieniarz, R. G. Pritchard, H. Weihe, L. Cronin, G.    Rajaraman, D. Collison, E. J. L. McInnes and R. E. P. Winpenny,    “Spin frustration in molecular magnets, a classification based on    physical studies of large odd-numbered-metal, odd-electron rings”,    Proc. Natl. Acad. Sci., 2012, 109, 19113-19118.

1. A method of performing electron-beam lithography, the methodcomprising: i) providing an (eBeam) resist-coated substrate or applyingan (eBeam) resist coating to a substrate; ii) exposing part(s) of the(eBeam) resist coating to (electron beam) radiation to provide anexposed (eBeam) resist coating; iii) developing the exposed (eBeam)resist coating to generate an (eBeam) resist pattern layer, the (eBeam)resist pattern layer comprising: developer-insoluble coating portions ofthe (eBeam) resist coating; and an array of grooves extending throughthe (eBeam) resist pattern layer; iv) optionally modifying thesubstrate, substrate surface, or part(s) thereof, underlying the (eBeam)resist pattern layer; v) optionally removing the (eBeam) resist patternlayer to provide a modified substrate; vi) optionally repeating, one ormore times, step iv) and/or steps i)-v) (optionally with an alternativeresist coating, such as a photoresist, instead of the eBeam resistcoating; and optionally using alternative radiation during exposure,such as visible or ultraviolet light, instead of electron beamradiation) upon the modified substrate; wherein the eBeam resist-coatedsubstrate is a substrate coated with an eBeam resist coating; whereinthe eBeam resist coating comprises an optionally dried and/or curedeBeam resist composition; wherein the eBeam resist composition comprisesan anti-scattering compound; wherein the anti-scattering compound has adensity less than or equal to 1.3 g/cm³ and a molecular weight greaterthan or equal to 2000 g/mol.
 2. (canceled)
 3. The method of claim 1,wherein the anti-scattering compound comprises a primary metal complex(PMC), wherein the primary metal complex is a polymetallic cage.
 4. Themethod of claim 3, wherein the anti-scattering compound comprises alinker component associated with one or more primary metal complexes ina hybrid complex of Formula B:(PMC)_(p)(LINK)_(l) wherein: PMC is a primary metal complex and p is avalue between 1 and 30 and is the number of moles of PMC per mole ofhybrid complex of Formula B; and wherein LINK is a linker component andl is a value between 1 and 10 and is the number of moles of LINK permole of hybrid complex of Formula B; wherein optionally either or bothof the primary metal complex(es) and/or linker component(s) within ahybrid complex are each independently associated with any of thecounterions, and/or the counterions may be associated with the hybridcomplex as a whole. wherein the anti-scattering compound optionallycomprises one or more counterions associated with the hybrid complex aspart of a hybrid complex salt, wherein the hybrid complex salt isdefined by Formula C:(C ¹ _(i1) C ² _(i2) . . . C ^(c) _(ic))(PMC)_(p)(LINK)_(l) wherein C¹is a first counterion, C² is a second counterion, and C^(c) is a cthcounterion, wherein i1, i2, and ic are the respective number of moles ofeach of C¹, C², . . . , and C^(c) per mole of hybrid complex salt ofFormula C.
 5. (canceled)
 6. The method of claim 3, wherein the primarymetal complex is defined by Formula I or comprises units defined byFormula I:[M ¹ _(x) M ² _(y . . .) M ^(n)_(zn)(monoLIG¹)_(m1)(monoLIG²)_(m2 . . .)(monoLIG^(q))_(mq)(biLIG¹)_(b1)(biLIG²)_(b2 . . .)(biLIG^(r))_(br)(optLIG^(s))(optLIG¹)_(o1)(optLIG²)_(o2 . . .)(optLIG^(s))_(os)]; wherein: M¹ is a first metal species and x is thenumber of moles of M¹ per mole of primary metal complex, wherein x is anumber between 1 and 16; M² is a second metal species and y is thenumber of moles of M² per mole of primary metal complex, wherein y is anumber between 0 and 7; M^(n) is an nth metal species and zn is thenumber of moles of each M^(n) per mole of primary metal complex, whereinzn is a number between 0 and 6; suitably between 0 and 2; suitably 0;monoLIG¹ is a first monodentate ligand and m1 is the number of moles ofmonoLIG¹ per mole of primary metal complex, wherein m1 is a numberbetween 0 and 20; monoLIG² is a second monodentate ligand and m2 is thenumber of moles of monoLIG² per mole of primary metal complex, whereinm2 is a number between 0 and 10; monoLIG^(q) is a qth monodentate ligandand mq is the number of moles of each monoLIG^(q) per mole of primarymetal complex, wherein mq is a number between 0 and 2; biLIG¹ is a firstbidentate ligand and b1 is the number of moles of biLIG¹ per mole ofprimary metal complex, wherein b1 is a number between 1 and 20; biLIG²is a second bidentate ligand and b2 is the number of moles of biLIG² permole of primary metal complex, wherein b2 is a number between 0 and 16;biLIG^(r) is a rth bidentate ligand and br is the number of moles ofeach additional biLIG^(r) per mole of primary metal complex, wherein bris a number between 0 and 2; optLIG¹ is a first optional extra ligandand o1 is the number of moles of optLIG¹ per mole of primary metalcomplex, wherein o1 is a number between 0 and 4; optLIG² is a secondoptional extra/terminal ligand and o2 is the number of moles of optLIG²per mole of primary metal complex, wherein o2 is a number between 0 and3; optLIG^(s) is a sth optional extra/terminal ligand and os is thenumber of moles of each additional optional optLIG^(s) per mole ofprimary metal complex; wherein os is a number between 0 and
 2. 7.(canceled)
 8. The method of claim 6, wherein the sum of x and y isbetween 4 and
 16. 9. The method of claim 6, wherein M¹ is a trivalentmetal species.
 10. The method of claim 6, wherein M² is a divalent metalspecies.
 11. The method of claim 9, wherein M¹ is a trivalent metalspecies selected from the group including Cr^(III), Fe^(III), V^(III),Ga^(III), Al^(III), or In^(III).
 12. (canceled)
 13. The method of claim10, wherein M² is a divalent metal species selected from the groupincluding Ni^(II), Co^(II), Zn^(II), Cd^(II), Mn^(II), Mg^(II), Ca^(II),Sr^(II), Ba^(II), Cu^(II), or Fe^(II).
 14. (canceled)
 15. (canceled) 16.The method of claim 6, wherein: biLIG¹ is a carboxylate defined by theformula —O₂CR_(B1) (or R_(B1)CO₂ ⁻), wherein R_(B1) is a hydrocarbylmoiety selected from (1-12C)alkyl, (1-12C)alkenyl, (1-12C)alkynyl,(3-8C)cycloalkyl, (3-8C)cycloalkenyl, (1-3C)alkyl(3-8C)cycloalkyl,(1-3C)alkyl(3-8C)cycloalkenyl, aryl, (1-3C)alkylaryl, oraryl(1-3C)alkyl. biLIG² is a carboxylate defined by the formula—O₂CR_(B2) (or R_(B2)CO₂ ⁻), wherein R_(B)2 is a group comprising abasic or chelating group, and is selected from optionally substitutedheterocyclyl, heteroaryl, heterocyclyl(1-6C)alkyl,heteroaryl(1-6C)alkyl, or is selected from (1-12C)alkyl, (1-12C)alkenyl,(1-12C)alkynyl, (3-8C)cycloalkyl, (3-8C)cycloalkenyl,(1-3C)alkyl(3-8C)cycloalkyl, (1-3C)alkyl(3-8C)cycloalkenyl, aryl,(1-3C)alkylaryl, or aryl(1-3C)alkyl. optLIG¹ is either a solventmolecule or a polydentate ligand having a denticity greater than orequal to
 3. 17. (canceled)
 18. The method of claim 16, wherein theprimary metal complex is defined or comprises units defined by either:by the Formula IIa: [M¹ _(8-y)M²_(y)F₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)] by the Formula IIb:[Cr₇NiF₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]; by the Formula IIc:[Cr₇NiF₈(O₂CR_(B1))₁₆]; by the Formula IId:[Cr₈F₈(O₂CR_(B1))_(16-b2)(O₂CR_(B2))_(b2)]; by the Formula IIe:[Cr₈F₈(O₂CR_(B1))₁₆]; or by the Formula III: [M¹ _(8-y)M²_(y)F₃(O₂CR_(B1))₁₅(Gluc-NH—R_(O1))], wherein Gluc-NH—R_(O1) isN-(1-8C)alkyl-D-glucamine.
 19. The method of claim 4, wherein the oreach linker component (LINK) is independently selected from: i) a singleatom, molecule, ion, or complex containing a single co-ordinating moietycapable of accepting or donating two or more lone pairs of electrons;ii) a single molecule, ion, or complex comprising two or moreco-ordinating moieties, each co-ordinating moiety being capable ofaccepting or donating one or more lone pairs of electrons; iii) amolecule, ion, or complex defined by Formula IV:Q-[CORE]-[W] _(w) wherein: [CORE] is absent or is the core of the linkercomponent and comprises one or optionally more than one core groups; Qis a group directly attached to [CORE] or to one or more core group(s)thereof, wherein Q comprises a co-ordinating moiety; each W is a groupindependently directly attached to [CORE] or to one or more coregroup(s) thereof, and optionally further attached to one or more other Wgroups or to Q, each of which W independently comprises a co-ordinatingmoiety; wherein w is an integer greater than zero.
 20. The method ofclaim 19, wherein the linker component is: a) a single atom, molecule,ion, or complex containing a single co-ordinating moiety capable ofdonating two or more lone pairs of electrons, and the linkercomponent(s) is or comprises a group selected from halide, oxo, oxide,hydroxide (OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy, (2-6C)alkynyloxy,formyl, carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl,(2-6C)alkanoyloxy, sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio,(2-6C)alkenylthio, (2-6C)alkynylthio, thiocarbonyl, heterocyclylcontaining at least one internal heteroatom selected from oxygen orsulphur, or (where appropriate) a deprotonated form or salt thereof;wherein any CH, CH₂, or CH₃ is optionally substituted; b) a single atom,molecule, ion, or complex containing a single co-ordinating moietycapable of accepting two or more lone pairs of electrons, and the linkercomponent(s) is or comprises a group selected from a metal cation, aLewis acidic metal compound, a Lewis acidic metal complex, and/or ametal compound or complex comprising a leaving group or substitutableligand; c) a single molecule, ion, or complex comprising two or moreco-ordinating moieties, each being capable of donating one or more lonepairs of electrons, and the linker component(s) is or comprises one ormore groups selected from halide, amino, cyano, imino, enamino,(1-6C)alkylamino, di-[(1-6C)alkyl]amino, tri-[(1-6C)alkyl]amino, oxo,oxide, hydroxide (OH⁻), (1-6C)alkoxide, (2-6C)alkenyloxy,(2-6C)alkynyloxy, formyl, carboxy, (1-6C)alkoxycarbonyl, (2-6C)alkanoyl,(2-6C)alkanoyloxy, sulpho, sulphide, hydrogensulphide, (1-6C)alkylthio,(2-6C)alkenylthio, (2-6C)alkynylthio, thiocarbonyl, heterocyclylcontaining at least one internal heteroatom selected from nitrogen,oxygen or sulphur, heteroaryl containing at least one internal heteroatom selected from nitrogen, oxygen or sulphur, or (where appropriate) adeprotonated form or salt thereof; wherein any CH, CH₂, or CH₃ isoptionally substituted; d) a single molecule, ion, or complex comprisingtwo or more co-ordinating moieties, each being capable of accepting oneor more lone pairs of electrons, and the linker component(s) is orcomprises one or more groups selected from a metal cation, a Lewisacidic metal compound, a Lewis acidic metal complex, and/or a metalcompound or complex comprising a leaving group or substitutable ligand;or e) a molecule, ion, or complex defined by Formula IV, and: (I) the[CORE] comprises a single core group to which the Q group and the oreach of the W group(s) are commonly attached, wherein the single coregroup is selected from: i) a divalent or multivalent optionallysubstituted acyclic core group; ii) a divalent or multivalent cyclic orpolycyclic core group; iii) a divalent or multivalent core groupcomprising at least one cyclic or polycyclic group linked to one or moreacyclic moieties and/or cyclic or polycyclic moieties; or iv) a divalentor multivalent macrocyclic core group; (II) the [CORE] comprises aplurality of core groups which are indirectly linked together to formthe [CORE] via the Q group and/or one or more of the or each of the Wgroup(s), wherein each of such core groups are independently selectedfrom: i) a single atom, molecule, ion, or complex containing a singleco-ordinating moiety capable of donating two or more lone pairs ofelectrons; and/or ii) a single molecule, ion, or complex comprising twoor more co-ordinating moieties each capable of independently donating anelectron lone pair; or (III) the [CORE], comprises a plurality of coregroups and is defined by:

wherein W and Q are electron pair-accepting Q and/or W groups; abd each[core] is such that the linker component is selected from: A dimetalliccarboxylate complex [M₂(O₂C^(R))₄] where M is a divalent metal ion; Adimetallic carboxylate complex [MM′(O₂C^(R))₄]⁺ where M is a divalentmetal ion; and M′ is a trivalent metal ion: A trimetallic carboxylatecomplex [M₃O(O₂CR)₆]⁺ where M is a trivalent metal ion; A trimetalliccarboxylate complex [M₂M′O(O₂CR)₆] where M is a trivalent metal ion, andM′ is a divalent metal ion; A hexametallic carboxylate complex[M′₄M₂O₂(O₂CR)₁₂] where M is a trivalent metal ion, and M′ is a divalentmetal ion; a dodecametallic complex M₁₂(chp)₁₂(O₂CMe)₆(H₂O)₆ wherechp=6-chloro-2-pyridonate, and where M=Ni or Co.
 21. (canceled) 22.(canceled)
 23. (canceled)
 24. The method of claim 1, wherein thesubstrate comprises or consists essentially of a substrate basematerial, wherein the substrate base material is a lithographic plate, amaterial for a lithographic mask, or an electronic component substrate.25. The method of claim 24, wherein the substrate base material is asingle monolithic silicon crystal.
 26. (canceled)
 27. The method ofclaim 1, wherein the eBeam resist composition further comprises asecondary electron generator which is or comprises a compound having aneffective atomic number (Z_(eff)) greater than or equal to 15, wherein:Z _(eff)=Σα_(i) Z _(i) where Z_(i) is the atomic number of the ithelement in the compound, and α_(i) is the fraction of the sum total ofthe atomic numbers of all atoms in the compound (i.e. the total numberof protons in the compound) constituted by said ith element. 28.(canceled)
 29. An eBeam resist composition comprising an anti-scatteringcompound; wherein the anti-scattering compound has a density less thanor equal to 1.3 g/cm³ and a molecular weight greater than or equal to2000 g/mol.
 30. (canceled)
 31. (canceled)
 32. A method of fabricating anintegrated circuit die or an integrated circuit wafer comprising aplurality of integrated circuit dice, the or each die comprising aplurality of electronic components, wherein the method comprisesperforming electron-beam lithography of claim 1 by: i) providing, asdefined in claim 1, an (eBeam) resist-coated substrate or applying, asdefined in claim 1, an (eBeam) resist coating to a substrate; and ii)exposing, as defined in claim 1, part(s) of the (eBeam) resist coatingto electron beam radiation to provide an exposed (eBeam) resist coating;iii) developing, as defined in claim 1, the exposed (eBeam) resistcoating to generate an (eBeam) resist pattern layer, the (eBeam) resistpattern layer comprising: developer-insoluble coating portions of the(eBeam) resist coating (i.e. ridges); and an array of grooves extendingthrough the (eBeam) resist pattern layer; iv) modifying, as defined inclaim 1, the substrate, substrate surface, or part(s) thereof,underlying the (eBeam) resist pattern layer; v) removing, as defined inclaim 1, the (eBeam) resist pattern layer to provide a modifiedsubstrate; vi) optionally repeating, as defined in claim 1, one or moretimes, step iv) and/or steps i)-v) upon the modified substrate, (usingeither an eBeam resist coating or an alternative resist coating, (e.g.,a photoresist); with either electron beam radiation or alternativeradiation during exposure; and thereafter vii) conductivelyinterconnecting the electronic components of the or each die withconductor(s), if not already performed during one or moresubstrate/substrate-surface modifying steps, to provide an integratedcircuit with external contact terminals; viii) optionally performing oneor more further finishing steps; ix) optionally separating an integratedcircuit die from a wafer comprising a plurality of integrated circuitdice; wherein the eBeam resist-coated substrate is a substrate coatedwith an eBeam resist coating; wherein the eBeam resist coating comprisesan optionally dried and/or cured resist composition; wherein the eBeamresist composition comprises an anti-scattering as defined in claim 1;wherein the resist-coated substrate is a substrate coated with a resistcoating, whether an eBeam resist coating as defined in claim 1 or analternative resist coating (e.g., a photoresist); wherein the resistcoating comprises an optionally dried and/or cured resist composition,whether an eBeam resist composition as defined in claim 1 or analternative resist composition (e.g., a photoresist).
 33. A method ofmanufacturing an integrated circuit package, the integrated circuitpackage comprising a plurality of pins and an integrated circuit diewith external contact terminals conductively connected to thecorresponding plurality of pins, wherein the method comprises providingan integrated circuit die by a method of fabricating an integratedcircuit die of claim 32; and thereafter: i) attaching the integratedcircuit die to a package substrate, wherein the package substratecomprises electrical contacts, each of the electrical contacts beingoptionally connected or connectable to a corresponding pin; ii)conductively connecting each of the external contact terminals of theintegrated circuit die to corresponding electrical contacts of thepackage substrate; and iii) optionally, and if necessary, connecting theelectrical contacts of the package substrate to corresponding pins; iv)encapsulating the integrated circuit die.
 34. A method of manufacturinga circuit board comprising an integrated circuit package comprising aplurality of pins, wherein the method comprises providing an integratedcircuit package by a method of manufacturing an integrated circuitpackage as claimed in claim 33; and thereafter: conductively connectingthe integrated circuit package to a circuit board.
 35. A method ofmanufacturing an electronic device or system, the electronic device orsystem comprising or being connectable to a power source and comprisinga circuit board conductively connected to or connectable to a powersource, wherein the method comprises providing a circuit board by themethod of manufacturing a circuit board as claimed in claim 34; andthereafter: incorporating the circuit board within the electronic deviceor system.
 36. (canceled)